U.S. patent application number 11/329928 was filed with the patent office on 2007-09-06 for egvii endoglucanase and nucleic acids encoding the same.
Invention is credited to Nigel Dunn-Coleman, Frits Goedegebuur, Michael Ward, Jian Yao.
Application Number | 20070207530 11/329928 |
Document ID | / |
Family ID | 21842358 |
Filed Date | 2007-09-06 |
United States Patent
Application |
20070207530 |
Kind Code |
A1 |
Dunn-Coleman; Nigel ; et
al. |
September 6, 2007 |
EGVII endoglucanase and nucleic acids encoding the same
Abstract
The present invention provides a novel endoglucanase nucleic
acid sequence, designated eg/7, and the corresponding EGVII amino
acid sequence. The invention also provides expression vectors and
host cells comprising a nucleic acid sequence encoding EGVII,
recombinant EGVII proteins and methods for producing the same.
Inventors: |
Dunn-Coleman; Nigel; (Los
Gatos, CA) ; Goedegebuur; Frits; (Vlaardingen,
NL) ; Ward; Michael; (San Francisco, CA) ;
Yao; Jian; (Sunnyvale, CA) |
Correspondence
Address: |
Genencor International, Inc.
925 Page Mill Road
Palo Alto
CA
94304-1013
US
|
Family ID: |
21842358 |
Appl. No.: |
11/329928 |
Filed: |
January 10, 2006 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10028244 |
Dec 18, 2001 |
7045331 |
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11329928 |
Jan 10, 2006 |
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Current U.S.
Class: |
435/161 |
Current CPC
Class: |
C12P 19/02 20130101;
C12Y 302/01004 20130101; C12N 9/2437 20130101; C12N 15/1137
20130101; C12N 9/2445 20130101; Y02E 50/10 20130101; C12P 19/14
20130101; Y02E 50/16 20130101; C12P 7/10 20130101; C12P 2201/00
20130101; Y02E 50/17 20130101; C11D 3/38 20130101; C11D 3/38645
20130101; C12N 2310/11 20130101; C12P 7/14 20130101; C11D 3/38636
20130101 |
Class at
Publication: |
435/161 |
International
Class: |
C12P 7/06 20060101
C12P007/06 |
Goverment Interests
GOVERNMENT SUPPORT
[0001] Portions of this work were funded by Subcontract No.
ZCO-30017-01 with the National Renewable Energy Laboratory under
Prime Contract No. DE-AC36-99GO10337 with the U.S. Department of
Energy. Accordingly, the United States Government may have certain
rights in this invention.
Claims
1-26. (canceled)
27. A method of producing ethanol, said method comprising the steps
of: a) contacting a biomass composition with an enzymatic
composition comprising endoglucanase 7 to yield a sugar solution;
b) adding to the sugar solution a fermentative microorganism; and
c) culturing the fermentative microorganism under conditions
sufficient to produce ethanol, wherein the biomass composition may
be optionally pretreated.
28. The method of claim 27 wherein step (a) further comprises the
addition of at least one endoglucanase.
29. The method of claim 27 wherein step (a) further comprises the
addition of at least one cellbiohydrolase.
30. The method of claim 28 wherein step (a) further comprises the
addition of at least one cellbiohydrolase.
31. The method of claim 27 wherein the pretreatment is with a
dilute acid.
32. A method of producing ethanol, said method comprising the steps
of: a) contacting a biomass composition with an enzymatic
composition comprising an endoglucanase 7 and a fermentative
microorganism; and b) culturing the fermentative microorganism
under conditions sufficient to produce ethanol, wherein the biomass
composition may be optionally pretreated.
33. The method of claim 32 wherein step (a) further comprises the
addition of at least one endoglucanase.
34. The method of claim 32 wherein step (a) further comprises the
addition of at least one cellbiohydrolase.
35. The method of claim 33 wherein step (a) further comprises the
addition of at least one cellbiohydrolase.
36. The method of claim 32 wherein the pretreatment is with a
dilute acid.
Description
FIELD OF THE INVENTION
[0002] The present invention relates to isolated eg/7 nucleic acid
sequences which encode polypeptides having endoglucanase activity.
The invention also relates to nucleic acid constructs, vectors, and
host cells comprising the nucleic acid sequences as well as methods
for producing recombinant EGVII polypeptides.
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BACKGROUND OF THE INVENTION
[0078] Cellulose and hemicellulose are the most abundant plant
materials produced by photosynthesis. They can be degraded and used
as an energy source by numerous microorganisms, including bacteria,
yeast and fungi, that produce extracellular enzymes capable of
hydrolysis of the polymeric substrates to monomeric sugars (Aro et
al., 2001). As the limits of non-renewable resources approach, the
potential of cellulose to become a major renewable energy resource
is enormous (Krishna et al., 2001). The effective utilization of
cellulose through biological processes is one approach to
overcoming the shortage of foods, feeds, and fuels (Ohmiya et al.,
1997).
[0079] Cellulases are enzymes that hydrolyze cellulose
(beta-1,4-glucan or beta D-glucosidic linkages) resulting in the
formation of glucose, cellobiose, cellooligosaccharides, and the
like. Cellulases have been traditionally divided into three major
classes: endoglucanases (EC 3.2.1.4) ("EG"), exoglucanases or
cellobiohydrolases (EC 3.2.1.91) ("CBH") and beta-glucosidases
([beta]-D-glucoside glucohydrolase; EC 3.2.1.21) ("BG"). (Knowles
et al., 1987; Shulein, 1988). Endoglucanases act mainly on the
amorphous parts of the cellulose fibre, whereas cellobiohydrolases
are also able to degrade crystalline cellulose (Nevalainen and
Penttila, 1995). Thus, the presence of a cellobiohydrolase in a
cellulase system is required for efficient solubilization of
crystalline cellulose (Suumakki, et al. 2000). Beta-glucosidase
acts to liberate D-glucose units from cellobiose,
cello-oligosaccharides, and other glucosides (Freer, 1993).
[0080] Cellulases are known to be produced by a large number of
bacteria, yeast and fungi. Certain fungi produce a complete
cellulase system capable of degrading crystalline forms of
cellulose, such that the cellulases are readily produced in large
quantities via fermentation. Filamentous fungi play a special role
since many yeast, such as Saccharomyces cerevisiae, lack the
ability to hydrolyze cellulose. See, e.g., Aro et al., 2001; Aubert
et al., 1988; Wood et al., 1988, and Coughlan, et al.
[0081] The fungal cellulase classifications of CBH, EG and BG can
be further expanded to include multiple components within each
classification. For example, multiple CBHs, EGs and BGs have been
isolated from a variety of fungal sources including Trichoderma
reesei which contains known genes for 2 CBHs, ie., CBH I and CBH
II, at least 5 EGs, i.e., EG I, EG II, EG III, EGIV and EGV, and at
least 2 BGs, i.e., BG1 and BG2.
[0082] In order to efficiently convert crystalline cellulose to
glucose the complete cellulase system comprising components from
each of the CBH, EG and BG classifications is required, with
isolated components less effective in hydrolyzing crystalline
cellulose (Filho et al., 1996). A synergistic relationship has been
observed between cellulase components from different
classifications. In particular, the EG-type cellulases and CBH-type
cellulases synergistically interact to more efficiently degrade
cellulose. See, e.g., Wood, 1985.
[0083] Cellulases are known in the art to be useful in the
treatment of textiles for the purposes of enhancing the cleaning
ability of detergent compositions, for use as a softening agent,
for improving the feel and appearance of cotton fabrics, and the
like (Kumar et al., 1997).
[0084] Cellulase-containing detergent compositions with improved
cleaning performance (U.S. Pat. No. 4,435,307; GB App. Nos.
2,095,275 and 2,094,826) and for use in the treatment of fabric to
improve the feel and appearance of the textile (U.S. Pat. Nos.
5,648,263, 5,691,178, and 5,776,757; GB App. No. 1,358,599; The
Shizuoka Prefectural Hammamatsu Textile Industrial Research
Institute Report, Vol. 24, pp. 54-61, 1986), have been
described.
[0085] Hence, cellulases produced in fungi and bacteria have
received significant attention. In particular, fermentation of
Trichoderma spp. (e.g., Trichoderma longibrachiatum or Trichoderma
reesei) has been shown to produce a complete cellulase system
capable of degrading crystalline forms of cellulose. U.S. Pat. No.
5,475,101 discloses the purification and molecular cloning of one
particularly useful enzyme designated EGIII which is derived from
Trichoderma longibrachiatum.
[0086] Although cellulase compositions have been previously
described, there remains a need for new and improved cellulase
compositions for use in household detergents, stonewashing
compositions or laundry detergents, etc. Cellulases that exhibit
resistance to surfactants (e.g., linear alkyl sulfonates, LAS),
improved performance under conditions of thermal stress, increased
or decreased cellulolytic capacity, and/or high level expression in
vitro, are of particular interest.
SUMMARY OF THE INVENTION
[0087] The invention provides an isolated cellulase protein,
identified herein as EGVII, and nucleic acids which encode
EGVII.
[0088] In one aspect, EGVII polypeptides or proteins comprise a
sequence having at least 80%, 85%, 90%, 95%, 98% or more sequence
identity to the sequence presented as SEQ ID NO:2.
[0089] In a related aspect, the invention includes (i) fragments of
EGVII, preferably at least about 20-100 amino acids in length, more
preferably about 100-200 amino acids in length, and (ii) a
pharmaceutical composition comprising EGVII. In various
embodiments, the fragment corresponds to the N-terminal domain of
EGVII or the C-terminal domain of EGVII.
[0090] In another aspect the invention includes an isolated
polynucleotide having a sequence, which encodes EGVII, a sequence
complementary to the eg/7 coding sequence, and a composition
comprising the polynucleotide. The polynucleotide may be mRNA, DNA,
cDNA, genomic DNA, or an antisense analog thereof.
[0091] An eg/7 polynucleotide may comprise an isolated nucleic acid
molecule which hybridizes to the complement of the nucleic acid
presented as SEQ ID NO: 1 under moderate to high stringency
conditions, where the nucleic acid molecule encodes an EGVII
polypeptide that exhibits endoglucanase activity.
[0092] The polynucleotide may encode an EGVII protein having at
least 80%, 85%, 90%, 95%, 98% or more sequence identity to the
sequence presented as SEQ ID NO:1. In a specific embodiment, the
polynucleotide comprises a sequence substantially identical to SEQ
ID NO:1. The invention also contemplates fragments of the
polynucleotide, preferably at least about 15-30 nucleotides in
length.
[0093] The invention further provides recombinant expression
vectors containing a nucleic acid sequence encoding EGVII or a
fragment or splice variant thereof, operably linked to regulatory
elements effective for expression of the protein in a selected
host. In a related aspect, the invention includes a host cell
containing the vector.
[0094] The invention further includes a method for producing EGVII
by recombinant techniques, by culturing recombinant prokaryotic or
eukaryotic host cells comprising nucleic acid sequence encoding
EGVII under conditions effective to promote expression of the
protein, and subsequent recovery of the protein from the host cell
or the cell culture medium.
[0095] In yet another aspect, the invention includes an antibody
specifically immunoreactive with EGVII.
[0096] Analytical methods for detecting eg/7 nucleic acids and
EGVII proteins also form part of the invention.
[0097] In another aspect the invention provides for an enzymatic
composition useful in the conversion of cellulose to sugars and/or
ethanol. In a preferred embodiment the enzymatic composition
comprises EGVII. The composition may further comprise additional
cellulase enzymes such as other endoglucanases, beta-glucosidases
and/or cellbiohydrolases. The composition may be enriched in
EGVII.
BRIEF DESCRIPTION FIGURES
[0098] FIG. 1 is a single stranded depiction of the nucleic acid
sequence (SEQ ID NO:1), of the T. reesei eg/7 cDNA, wherein the
non-coding sequence is indicated as bolded.
[0099] FIG. 2 shows the predicted amino acid sequence (SEQ ID NO:2)
and signal sequence (SEQ ID NO:3) based on the nucleotide sequence
provided in FIG. 1, wherein the signal sequence is indicated as
bolded.
DETAILED DESCRIPTION OF THE INVENTION
I. Definitions.
[0100] Unless otherwise indicated, all technical and scientific
terms used herein have the same meaning as they would to one
skilled in the art of the present invention. Practitioners are
particularly directed to Sambrook et al., 1989, and Ausubel F M et
al., 1993, for definitions and terms of the art. It is to be
understood that this invention is not limited to the particular
methodology, protocols, and reagents described, as these may
vary.
[0101] All publications cited herein are expressly incorporated
herein by reference for the purpose of describing and disclosing
compositions and methodologies which might be used in connection
with the invention.
[0102] The term "polypeptide" as used herein refers to a compound
made up of a single chain of amino acid residues linked by peptide
bonds. The term "protein" as used herein may be synonymous with the
term "polypeptide" or may refer, in addition, to a complex of two
or more polypeptides.
[0103] The term "nucleic acid molecule" includes RNA, DNA and cDNA
molecules. It will be understood that, as a result of the
degeneracy of the genetic code, a multitude of nucleotide sequences
encoding a given protein such as EGVII may be produced. The present
invention contemplates every possible variant nucleotide sequence,
encoding EGVII, all of which are possible given the degeneracy of
the genetic code.
[0104] A "heterologous" nucleic acid construct or sequence has a
portion of the sequence, which is not native to the cell in which
it is expressed. Heterologous, with respect to a control sequence
refers to a control sequence (i.e. promoter or enhancer) that does
not function in nature to regulate the same gene the expression of
which it is currently regulating. Generally, heterologous nucleic
acid sequences are not endogenous to the cell or part of the genome
in which they are present, and have been added to the cell, by
infection, transfection, transformation, microinjection,
electroporation, or the like. A "heterologous" nucleic acid
construct may contain a control sequence/DNA coding sequence
combination that is the same as, or different from a control
sequence/DNA coding sequence combination found in the native
cell.
[0105] As used herein, the term "vector" refers to a nucleic acid
construct designed for transfer between different host cells. An
"expression vector" refers to a vector that has the ability to
incorporate and express heterologous DNA fragments in a foreign
cell. Many prokaryotic and eukaryotic expression vectors are
commercially available. Selection of appropriate expression vectors
is within the knowledge of those having skill in the art.
[0106] Accordingly, an "expression cassette" or "expression vector"
is a nucleic acid construct generated recombinantly or
synthetically, with a series of specified nucleic acid elements
that permit transcription of a particular nucleic acid in a target
cell. The recombinant expression cassette can be incorporated into
a plasmid, chromosome, mitochondrial DNA, plastid DNA, virus, or
nucleic acid fragment. Typically, the recombinant expression
cassette portion of an expression vector includes, among other
sequences, a nucleic acid sequence to be transcribed and a
promoter.
[0107] As used herein, the term "plasmid" refers to a circular
double-stranded (ds) DNA construct used as a cloning vector, and
which forms an extrachromosomal self-replicating genetic element in
many bacteria and some eukaryotes.
[0108] As used herein, the term "selectable marker-encoding
nucleotide sequence" refers to a nucleotide sequence which is
capable of expression in cells and where expression of the
selectable marker confers to cells containing the expressed gene
the ability to grow in the presence of a corresponding selective
agent, or under corresponding selective growth conditions.
[0109] As used herein, the term "promoter" refers to a nucleic acid
sequence that functions to direct transcription of a downstream
gene. The promoter will generally be appropriate to the host cell
in which the target gene is being expressed. The promoter together
with other transcriptional and translational regulatory nucleic
acid sequences (also termed "control sequences") are necessary to
express a given gene. In general, the transcriptional and
translational regulatory sequences include, but are not limited to,
promoter sequences, ribosomal binding sites, transcriptional start
and stop sequences, translational start and stop sequences, and
enhancer or activator sequences.
[0110] "Chimeric gene" or "heterologous nucleic acid construct", as
defined herein refers to a non-native gene (i.e., one that has been
introduced into a host) that may be composed of parts of different
genes, including regulatory elements. A chimeric gene construct for
transformation of a host cell is typically composed of a
transcriptional regulatory region (promoter) operably linked to a
heterologous protein coding sequence, or, in a selectable marker
chimeric gene, to a selectable marker gene encoding a protein
conferring antibiotic resistance to transformed cells. A typical
chimeric gene of the present invention, for transformation into a
host cell, includes a transcriptional regulatory region that is
constitutive or inducible, a protein coding sequence, and a
terminator sequence. A chimeric gene construct may also include a
second DNA sequence encoding a signal peptide if secretion of the
target protein is desired.
[0111] A nucleic acid is "operably linked" when it is placed into a
functional relationship with another nucleic acid sequence. For
example, DNA encoding a secretory leader is operably linked to DNA
for a polypeptide if it is expressed as a preprotein that
participates in the secretion of the polypeptide; a promoter or
enhancer is operably linked to a coding sequence if it affects the
transcription of the sequence; or a ribosome binding site is
operably linked to a coding sequence if it is positioned so as to
facilitate translation. Generally, "operably linked" means that the
DNA sequences being linked are contiguous, and, in the case of a
secretory leader, contiguous and in reading frame. However,
enhancers do not have to be contiguous. Linking is accomplished by
ligation at convenient restriction sites. If such sites do not
exist, the synthetic oligonucleotide adaptors, linkers or primers
for PCR are used in accordance with conventional practice.
[0112] As used herein, the term "gene" means the segment of DNA
involved in producing a polypeptide chain, that may or may not
include regions preceding and following the coding region, e.g. 5'
untranslated (5' UTR) or "leader" sequences and 3' UTR or "trailer"
sequences, as well as intervening sequences (introns) between
individual coding segments (exons).
[0113] In general, nucleic acid molecules which encode EGVII or an
analog or homologue thereof will hybridize, under moderate to high
stringency conditions to the sequence provided herein as SEQ ID
NO:1. However, in some cases an EGVII-encoding nucleotide sequence
is employed that possesses a substantially different codon usage,
while the protein encoded by the EGVII-encoding nucleotide sequence
has the same or substantially the same amino acid sequence as the
native protein. For example, the coding sequence may be modified to
facilitate faster expression of EGVII in a particular prokaryotic
or eukaryotic expression system, in accordance with the frequency
with which a particular codon is utilized by the host. Te'o, et al.
(2000), for example, describes the optimization of genes for
expression in filamentous fungi.
[0114] A nucleic acid sequence is considered to be "selectively
hybridizable" to a reference nucleic acid sequence if the two
sequences specifically hybridize to one another under moderate to
high stringency hybridization and wash conditions. Hybridization
conditions are based on the melting temperature (Tm) of the nucleic
acid binding complex or probe. For example, "maximum stringency"
typically occurs at about Tm-5.degree. C. (5.degree. below the Tm
of the probe); "high stringency" at about 5-10.degree. below the
Tm; "intermediate stringency" at about 10-20.degree. below the Tm
of the probe; and "low stringency" at about 20-25.degree. below the
Tm. Functionally, maximum stringency conditions may be used to
identify sequences having strict identity or near-strict identity
with the hybridization probe; while high stringency conditions are
used to identify sequences having about 80% or more sequence
identity with the probe.
[0115] Moderate and high stringency hybridization conditions are
well known in the art (see, for example, Sambrook, et al., 1989,
Chapters 9 and 11, and in Ausubel, F. M., et al., 1993, expressly
incorporated by reference herein). An example of high stringency
conditions includes hybridization at about 42.degree. C. in 50%
formamide, 5.times.SSC, 5.times. Denhardt's solution, 0.5% SDS and
100 .mu.g/ml denatured carrier DNA followed by washing two times in
2.times.SSC and 0.5% SDS at room temperature and two additional
times in 0.1.times.SSC and 0.5% SDS at 42.degree. C.
[0116] As used herein, "recombinant" includes reference to a cell
or vector, that has been modified by the introduction of a
heterologous nucleic acid sequence or that the cell is derived from
a cell so modified. Thus, for example, recombinant cells express
genes that are not found in identical form within the native
(non-recombinant) form of the cell or express native genes that are
otherwise abnormally expressed, under expressed or not expressed at
all as a result of deliberate human intervention.
[0117] As used herein, the terms "transformed", "stably
transformed" or "transgenic" with reference to a cell means the
cell has a non-native (heterologous) nucleic acid sequence
integrated into its genome or as an episomal plasmid that is
maintained through multiple generations.
[0118] As used herein, the term "expression" refers to the process
by which a polypeptide is produced based on the nucleic acid
sequence of a gene. The process includes both transcription and
translation.
[0119] The term "introduced" in the context of inserting a nucleic
acid sequence into a cell, means "transfection", or
"transformation" or "transduction" and includes reference to the
incorporation of a nucleic acid sequence into a eukaryotic or
prokaryotic cell where the nucleic acid sequence may be
incorporated into the genome of the cell (for example, chromosome,
plasmid, plastid, or mitochondrial DNA), converted into an
autonomous replicon, or transiently expressed (for example,
transfected mRNA).
[0120] It follows that the term "EGVII expression" refers to
transcription and translation of the eg/7 gene, the products of
which include precursor RNA, mRNA, polypeptide,
post-translationally processed polypeptides, and derivatives
thereof, including EGVII from related species such as Trichoderma
longibrachiatum (reesei), Trichoderma viride, Trichoderma koningii,
Hypocrea jecorina and Hypocrea schweinitzii. By way of example,
assays for EGVII expression include Western blot for EGVII protein,
Northern blot analysis and reverse transcriptase polymerase chain
reaction (RT-PCR) assays for EGVII mRNA, and endoglucanase activity
assays as described in Shoemaker S. P. and Brown R. D. Jr.
(Biochim. Biophys. Acta, 1978, 523:133-146) and Schulein
(1988).
[0121] The term "alternative splicing" refers to the process
whereby multiple polypeptide isoforms are generated from a single
gene, and involves the splicing together of nonconsecutive exons
during the processing of some, but not all, transcripts of the
gene. Thus a particular exon may be connected to any one of several
alternative exons to form messenger RNAs. The alternatively-spliced
mRNAs produce polypeptides ("splice variants") in which some parts
are common while other parts are different.
[0122] The term "signal sequence" refers to a sequence of amino
acids at the N-terminal portion of a protein, which facilitates the
secretion of the mature form of the protein outside the cell. The
mature form of the extracellular protein lacks the signal sequence
which is cleaved off during the secretion process.
[0123] By the term "host cell" is meant a cell that contains a
vector and supports the replication, and/or transcription or
transcription and translation (expression) of the expression
construct. Host cells for use in the present invention can be
prokaryotic cells, such as E. coli, or eukaryotic cells such as
yeast, plant, insect, amphibian, or mammalian cells. In general,
host cells are filamentous fungi.
[0124] The term "filamentous fungi" means any and all filamentous
fungi recognized by those of skill in the art. A preferred fungus
is selected from the group consisting of Aspergillus, Trichoderma,
Fusarium, Chrysosporium, Penicillium, Humicola, Neurospora, or
alternative sexual forms thereof such as Emericella, Hypocrea.
[0125] The term "cellooligosaccharide" refers to oligosaccharide
groups containing from 2-8 glucose units and having .beta.-1,4
linkages, e.g., cellobiose.
[0126] The term "cellulase" refers to a category of enzymes capable
of hydrolyzing cellulose polymers to shorter cello-oligosaccharide
oligomers, cellobiose and/or glucose. Numerous examples of
cellulases, such as exoglucanases, exocellobiohydrolases,
endoglucanases, and glucosidases have been obtained from
cellulolytic organisms, particularly including fungi, plants and
bacteria.
[0127] The term "cellulose binding domain" as used herein refers to
portion of the amino acid sequence of a cellulase or a region of
the enzyme that is involved in the cellulose binding activity of a
cellulase or derivative thereof. Cellulose binding domains
generally function by non-covalently binding the cellulase to
cellulose, a cellulose derivative or other polysaccharide
equivalent thereof. Cellulose binding domains permit or facilitate
hydrolysis of cellulose fibers by the structurally distinct
catalytic core region, and typically function independent of the
catalytic core. Thus, a cellulose binding domain will not possess
the significant hydrolytic activity attributable to a catalytic
core. In other words, a cellulose binding domain is a structural
element of the cellulase enzyme protein tertiary structure that is
distinct from the structural element which possesses catalytic
activity.
[0128] As used herein, the term "surfactant" refers to any compound
generally recognized in the art as having surface active qualities.
Thus, for example, surfactants comprise anionic, cationic and
nonionic surfactants such as those commonly found in detergents.
Anionic surfactants include linear or branched
alkylbenzenesulfonates; alkyl or alkenyl ether sulfates having
linear or branched alkyl groups or alkenyl groups; alkyl or alkenyl
sulfates; olefinsulfonates; and alkanesulfonates. Ampholytic
surfactants include quaternary ammonium salt sulfonates, and
betaine-type ampholytic surfactants. Such ampholytic surfactants
have both the positive and negative charged groups in the same
molecule. Nonionic surfactants may comprise polyoxyalkylene ethers,
as well as higher fatty acid alkanolamides or alkylene oxide adduct
thereof, fatty acid glycerine monoesters, and the like.
[0129] As used herein, the term "cellulose containing fabric"
refers to any sewn or unsewn fabrics, yams or fibers made of cotton
or non-cotton containing cellulose or cotton or non-cotton
containing cellulose blends including natural cellulosics and
manmade cellulosics (such as jute, flax, ramie, rayon, and
lyocell).
[0130] As used herein, the term "cotton-containing fabric" refers
to sewn or unsewn fabrics, yams or fibers made of pure cotton or
cotton blends including cotton woven fabrics, cotton knits, cotton
denims, cotton yams, raw cotton and the like.
[0131] As used herein, the term "stonewashing composition" refers
to a formulation for use in stonewashing cellulose containing
fabrics. Stonewashing compositions are used to modify cellulose
containing fabrics prior to sale, i.e., during the manufacturing
process. In contrast, detergent compositions are intended for the
cleaning of soiled garments and are not used during the
manufacturing process.
[0132] As used herein, the term "detergent composition" refers to a
mixture which is intended for use in a wash medium for the
laundering of soiled cellulose containing fabrics. In the context
of the present invention, such compositions may include, in
addition to cellulases and surfactants, additional hydrolytic
enzymes, builders, bleaching agents, bleach activators, bluing
agents and fluorescent dyes, caking inhibitors, masking agents,
cellulase activators, antioxidants, and solubilizers.
[0133] As used herein, the term "decrease or elimination in
expression of the eg/7 gene" means that either that the eg/7 gene
has been deleted from the genome and therefore cannot be expressed
by the recombinant host microorganism; or that the eg/7 gene has
been modified such that a functional EGVII enzyme is not produced
by the recombinant host microorganism.
[0134] The term "altered eg/7" or "altered eg/7 gene" means that
the nucleic acid sequence of the gene has been altered by removing,
adding, and/or manipulating the coding sequence or the amino acid
sequence of the expressed protein has been modified.
[0135] As used herein, the term "purifying" generally refers to
subjecting transgenic nucleic acid or protein containing cells to
biochemical purification and/or column chromatography.
[0136] As used herein, the terms "active" and "biologically active"
refer to a biological activity associated with a particular
protein, such as the enzymatic activity associated with a protease.
It follows that the biological activity of a given protein refers
to any biological activity typically attributed to that protein by
those of skill in the art.
[0137] As used herein, the term "enriched" means that the EGVII is
found in a concentration that is greater relative to the EGVII
concentration found in a wild-type, or naturally occurring, fungal
cellulase composition. The terms enriched, elevated and enhanced
may be used interchangeably herein.
[0138] A wild type fungal cellulase composition is one produced by
a naturally occurring fungal source and which comprises one or more
BGL, CBH and EG components wherein each of these components is
found at the ratio produced by the fungal source. Thus, an enriched
EGVII composition would have EGVII at an altered ratio wherein the
ratio of EGVII to other cellulase components (i.e., CBHs,
beta-glucosidases and other endoglucanases) is elevated. This ratio
may be increased by either increasing EGVII or decreasing (or
eliminating) at least one other component by any means known in the
art.
[0139] Thus, to illustrate, a naturally occurring cellulase system
may be purified into substantially pure components by recognized
separation techniques well published in the literature, including
ion exchange chromatography at a suitable pH, affinity
chromatography, size exclusion and the like. For example, in ion
exchange chromatography (usually anion exchange chromatography), it
is possible to separate the cellulase components by eluting with a
pH gradient, or a salt gradient, or both a pH and a salt gradient.
The purified EGVII may then be added to the enzymatic solution
resulting in an enriched EGVII solution. It is also possible to
elevate the amount of EGVII produced by a microbe using molecular
genetics methods to overexpress the gene encoding EGVII, possibly
in conjunction with deletion of one or more genes encoding other
cellulases.
[0140] Fungal cellulases may contain more than one EG component.
The different components generally have different isoelectric
points which allow for their separation via ion exchange
chromatography and the like. Either a single EG component or a
combination of EG components may be employed in an enzymatic
solution.
[0141] When employed in enzymatic solutions, the EG component is
generally added in an amount sufficient to allow the highest rate
of release of soluble sugars from the biomass. The amount of EG
component added depends upon the type of biomass to be saccharified
which can be readily determined by the skilled artisan. However,
when employed, the weight percent of the EGVIII component relative
to any CBH type components present in the cellulase composition is
from preferably about 1, preferably about 5, preferably about 10,
preferably about 15, or preferably about 20 weight percent to
preferably about 25, preferably about 30, preferably about 35,
preferably about 40, preferably about 45 or preferably about 50
weight percent. Furthermore, preferred ranges may be about 0.5 to
about 15 weight percent, about 0.5 to about 20 weight percent, from
about 1 to about 10 weight percent, from about 1 to about 15 weight
percent, from about 1 to about 20 weight percent, from about 1 to
about 25 weight percent, from about 5 to about 20 weight percent,
from about 5 to about 25 weight percent, from about 5 to about 30
weight percent, from about 5 to about 35 weight percent, from about
5 to about 40 weight percent, from about 5 to about 45 weight
percent, from about 5 to about 50 weight percent, from about 10 to
about 20 weight percent, from about 10 to about 25 weight percent,
from about 10 to about 30 weight percent, from about 10 to about 35
weight percent, from about 10 to about 40 weight percent, from
about 10 to about 45 weight percent, from about 10 to about 50
weight percent, from about 15 to about 20 weight percent, from
about 15 to about 25 weight percent, from about 15 to about 30
weight percent, from about 15 to about 35 weight percent, from
about 15 to about 30 weight percent, from about 15 to about 45
weight percent, from about 15 to about 50 weight percent.
II. Target Organisms
[0142] A. Filamentous Fungi
[0143] Filamentous fungi include all filamentous forms of the
subdivision Eumycota and Oomycota. The filamentous fungi are
characterized by vegetative mycelium having a cell wall composed of
chitin, glucan, chitosan, mannan, and other complex
polysaccharides, with vegetative growth by hyphal elongation and
carbon catabolism that is obligately aerobic.
[0144] In the present invention, the filamentous fungal parent cell
may be a cell of a species of, but not limited to, Trichoderma,
e.g., Trichoderma longibrachiatum (reesei), Trichoderma viride,
Trichoderma koningii, Trichoderma harzianum; Penicillium sp.;
Humicola sp., including Humicola insolens; Chrysosporium sp.,
including C. lucknowense; Gliocladium sp.; Aspergillus sp.;
Fusarium sp., Neurospora sp., Hypocrea sp., and Emericella sp. As
used herein, the term "Trichoderma" or "Trichoderma sp." refers to
any fungal strains which have previously been classified as
Trichoderma or are currently classified as Trichoderma.
[0145] In one preferred embodiment, the filamentous fungal parent
cell is an Aspergillus niger, Aspergillus awamori, Aspergillus
aculeatus, or Aspergillus nidulans cell.
[0146] In another preferred embodiment, the filamentous fungal
parent cell is a Trichoderma reesei cell.
III. Cellulases
[0147] Cellulases are known in the art as enzymes that hydrolyze
cellulose (beta-1,4-glucan or beta D-glucosidic linkages) resulting
in the formation of glucose, cellobiose, cellooligosaccharides, and
the like. As set forth above, cellulases have been traditionally
divided into three major classes: endoglucanases (EC 3.2.1.4)
("EG"), exoglucanases or cellobiohydrolases (EC 3.2.1.91) ("CBH")
and beta-glucosidases (EC 3.2.1.21) ("BG"). (Knowles, et al., 1987;
Schulein, 1988).
[0148] Certain fungi produce complete cellulase systems which
include exo-cellobiohydrolases or CBH-type cellulases,
endoglucanases or EG-type cellulases and beta-glucosidases or
BG-type cellulases (Schulein, 1988). However, sometimes these
systems lack CBH-type cellulases and bacterial cellulases also
typically include little or no CBH-type cellulases. In addition, it
has been shown that the EG components and CBH components
synergistically interact to more efficiently degrade cellulose.
See, e.g., Wood, 1985. The different components, i.e., the various
endoglucanases and exocellobiohydrolases in a multi-component or
complete cellulase system, generally have different properties,
such as isoelectric point, molecular weight, degree of
glycosylation, substrate specificity and enzymatic action
patterns.
[0149] It is believed that endoglucanase-type cellulases hydrolyze
internal beta-1,4-glucosidic bonds in regions of low crystallinity
of the cellulose and exo-cellobiohydrolase-type cellulases
hydrolyze cellobiose from the reducing or non-reducing end of
cellulose. It follows that the action of endoglucanase components
can greatly facilitate the action of exo-cellobiohydrolases by
creating new chain ends which are recognized by
exo-cellobiohydrolase components. Further, beta-glucosidase-type
cellulases have been shown to catalyze the hydrolysis of alkyl
and/or aryl .beta.-D-glucosides such as methyl .beta.-D-glucoside
and p-nitrophenyl glucoside as well as glycosides containing only
carbohydrate residues, such as cellobiose. This yields glucose as
the sole product for the microorganism and reduces or eliminates
cellobiose which inhibits cellobiohydrolases and
endoglucanases.
[0150] Accordingly, .beta.-glucosidase-type cellulases are
considered to be an integral part of the cellulase system because
they drive the overall reaction to glucose. Increased expression of
BG in T. reesei has been shown to improve degradation of cellulose
to glucose. See EP0562003, which is hereby incorporated by
reference. In addition, .alpha.-glucosidases can catalyze the
hydrolysis of a number of different substrates, and therefore they
find utility in a variety of different applications. Some
.beta.-glucosidases can be added to grapes during wine making to
enhance the potential aroma of the finished wine product. Yet
another application can be to use .beta.-glucosidase in fruit to
enhance the aroma thereof. Alternatively, .beta.-glucosidase can be
used directly in food additives or wine processing to enhance the
flavor and aroma.
[0151] Cellulases also find a number of uses in detergent
compositions including to enhance cleaning ability, as a softening
agent and to improve the feel of cotton fabrics (Hemmpel, 1991;
Tyndall, 1992; Kumar et al., 1997). While the mechanism is not part
of the invention, softening and color restoration properties of
cellulase have been attributed to the alkaline endoglucanase
components in cellulase compositions, as exemplified by U.S. Pat.
Nos. 5,648,263, 5,691,178, and 5,776,757, which disclose that
detergent compositions containing a cellulase composition enriched
in a specified alkaline endoglucanase component impart color
restoration and improved softening to treated garments as compared
to cellulase compositions not enriched in such a component. In
addition, the use of such alkaline endoglucanase components in
detergent compositions has been shown to complement the pH
requirements of the detergent composition (e.g., by exhibiting
maximal activity at an alkaline pH of 7.5 to 10, as described in
U.S. Pat. Nos. 5,648,263, 5,691,178, and 5,776,757).
[0152] Cellulase compositions have also been shown to degrade
cotton-containing fabrics, resulting in reduced strength loss in
the fabric (U.S. Pat. No. 4,822,516), contributing to reluctance to
use cellulase compositions in commercial detergent applications.
Cellulase compositions comprising endoglucanase components have
been suggested to exhibit reduced strength loss for
cotton-containing fabrics as compared to compositions comprising a
complete cellulase system.
[0153] Cellulases have also been shown to be useful in degradation
of cellulase biomass to ethanol (wherein the cellulase degrades
cellulose to glucose and yeast or other microbes further ferment
the glucose into ethanol), in the treatment of mechanical pulp
(Pere et al., 1996), for use as a feed additive (WO 91/04673) and
in grain wet milling.
[0154] Most CBHs and EGs have a multidomain structure consisting of
a core domain separated from a cellulose binding domain (CBD) by a
linker peptide (Suurnakki et al., 2000). The core domain contains
the active site whereas the CBD interacts with cellulose by binding
the enzyme to it (van Tilbeurgh et al., 1986; Tomme et al., 1988).
The CBDs are particularly important in the hydrolysis of
crystalline cellulose. It has been shown that the ability of
cellobiohydrolases to degrade crystalline cellulose clearly
decreases when the CBD is absent (Linder and Teeri, 1997). However,
the exact role and action mechanism of CBDs is still a matter of
speculation. It has been suggested that the CBD enhances the
enzymatic activity merely by increasing the effective enzyme
concentration at the surface of cellulose (Stahlberg et al., 1991),
and/or by loosening single cellulose chains from the cellulose
surface (Tormo et al., 1996). Most studies concerning the effects
of cellulase domains on different substrates have been carried out
with core proteins of cellobiohydrolases, as their core proteins
can easily be produced by limited proteolysis with papain (Tomme et
al., 1988). Numerous cellulases have been described in the
scientific literature, examples of which include: from Trichoderma
reesei: Shoemaker, S. et al., Bio/Technology, 1:691-696, 1983,
which discloses CBHI; Teeri, T. et al., Gene, 51:43-52, 1987, which
discloses CBHII; Penttila, M. et al., Gene, 45:253-263, 1986, which
discloses EGI; Saloheimo, M. et al., Gene, 63:11-22, 1988, which
discloses EGII; Okada, M. et al., Appl. Environ. Microbiol.,
64:555-563, 1988, which discloses EGIII; Saloheimo, M. et al., Eur.
J. Biochem., 249:584-591, 1997, which discloses EGIV; Saloheimo, A.
et al., Molecular Microbiology, 13:219-228, 1994, which discloses
EGV; Barnett, C. C., et al., Bio/Technology, 9:562-567, 1991, which
discloses BGL1, and Takashima, S. et al., J. Biochem., 125:728-736,
1999, which discloses BGL2. Cellulases from species other than
Trichoderma have also been described e.g., Ooi et al., 1990, which
discloses the cDNA sequence coding for endoglucanase F1-CMC
produced by Aspergillus aculeatus; Kawaguchi T et al., 1996, which
discloses the cloning and sequencing of the cDNA encoding
beta-glucosidase 1 from Aspergillus aculeatus; Sakamoto et al.,
1995, which discloses the cDNA sequence encoding the endoglucanase
CMCase-1 from Aspergillus kawachii IFO 4308; Saarilahti et al.,
1990 which discloses an endoglucanase from Erwinia carotovara;
Spilliaert R, et al., 1994, which discloses the cloning and
sequencing of bglA, coding for a thermostable beta-glucanase from
Rhodothermus marinu; and Halldorsdottir S et al., 1998, which
discloses the cloning, sequencing and overexpression of a
Rhodothermus marinus gene encoding a thermostable cellulase of
glycosyl hydrolase family 12. However, there remains a need for
identification and characterization of novel cellulases, with
improved properties, such as improved performance under conditions
of thermal stress or in the presence of surfactants, increased
specific activity, altered substrate cleavage pattern, and/or high
level expression in vitro.
[0155] The development of new and improved cellulase compositions
that comprise varying amounts CBH-type, EG-type and BG-type
cellulases is of interest for use: (1) in detergent compositions
that exhibit enhanced cleaning ability, function as a softening
agent and/or improve the feel of cotton fabrics (e.g., "stone
washing" or "biopolishing"); (2) in compositions for degrading wood
pulp or other biomass into sugars (e.g., for bio-ethanol
production); and/or (3) in feed compositions.
IV. Methods of Identifying Novel Sequences
[0156] Open reading frames (ORFs) are analyzed following full or
partial sequencing of the T. reesei genome or of clones of cDNA
libraries derived from T. reesei mRNA and are further analyzed
using sequence analysis software, and by determining homology to
known sequences in databases (public/private).
V. eg/7 Nucleic Acids and EGVII Polypeptides.
[0157] A. eg/7 Nucleic Acids
[0158] The nucleic acid molecules of the present invention include
the native coding sequence for eg/7. In one embodiment the sequence
is the cDNA sequence for eg/7 presented herein as SEQ. ID. NO:1 or
SEQ. ID. NO:4, and homologues thereof in other species, naturally
occurring allelic and splice variants, nucleic acid fragments, and
biologically active (functional) derivatives thereof, such as,
amino acid sequence variants of the native molecule and sequences
which encode fusion proteins. The sequences are collectively
referred to herein as "EGVII-encoding nucleic acid sequences".
[0159] A Basic BLASTN search (http://www.ncbi.nlm.nih.gov/BLAST) of
the non-redundant nucleic acid sequence database was conducted on
Sep. 12, 2001, with the eg/7 gene sequence presented in FIG. 1 (SEQ
ID NO:1), indicated no sequences producing significant alignments
(i.e. with an E value of less than 10.sup.-5).
[0160] An eg/7 nucleic acid sequence of this invention may be a DNA
or RNA sequence, derived from genomic DNA, cDNA, mRNA, or may be
synthesized in whole or in part. The DNA may be double-stranded or
single-stranded and if single-stranded may be the coding strand or
the non-coding (antisense, complementary) strand. The nucleic acid
sequence may be cloned, for example, by isolating genomic DNA from
an appropriate source, and amplifying and cloning the sequence of
interest using a polymerase chain reaction (PCR). Alternatively,
nucleic acid sequence may be synthesized, either completely or in
part, especially where it is desirable to provide host-preferred
sequences for optimal expression. Thus, all or a portion of the
desired structural gene (that portion of the gene which encodes a
polypeptide or protein) may be synthesized using codons preferred
by a selected host.
[0161] Due to the inherent degeneracy of the genetic code, nucleic
acid sequences other than the native form which encode
substantially the same or a functionally equivalent amino acid
sequence may be used to clone and/or express EGVII-encoding nucleic
acid sequences. Thus, for a given EGVII-encoding nucleic acid
sequence, it is appreciated that as a result of the degeneracy of
the genetic code, a number of coding sequences can be produced that
encode a protein having the same amino acid sequence. For example,
the triplet CGT encodes the amino acid arginine. Arginine is
alternatively encoded by CGA, CGC, CGG, AGA, and AGG. Therefore it
is appreciated that such substitutions in the coding region fall
within the nucleic acid sequence variants covered by the present
invention. Any and all of these sequence variants can be utilized
in the same way as described herein for the native form of an
EGVII-encoding nucleic add sequence.
[0162] A "variant" EGVII-encoding nucleic acid sequence may encode
a "variant" EGVII amino acid sequence which is altered by one or
more amino acids from the native polypeptide sequence or may be
truncated by removal of one or more amino acids from either end of
the polypeptide sequence, both of which are included within the
scope of the invention. Similarly, the term "modified form of",
relative to EGVII, means a derivative or variant form of the native
EGVII protein-encoding nucleic acid sequence or the native EGVII
amino acid sequence.
[0163] Similarly, the polynucleotides for use in practicing the
invention include sequences which encode native EGVII proteins and
splice variants thereof, sequences complementary to the native
protein coding sequence, and novel fragments of EGVII encoding
polynucleotides. An EGVII encoding nucleic acid sequence may
contain one or more intron sequences if it is a genomic DNA
sequence.
[0164] In one general embodiment, an EGVII-encoding nucleotide
sequence has at least 70%, preferably 80%, 85%, 90%, 95%, 98%, or
more sequence identity to the eg/7 coding sequence presented herein
as SEQ ID NO:1.
[0165] In another embodiment, an EGVII-encoding nucleotide sequence
will hybridize under moderate to high stringency conditions to a
nucleotide sequence that encodes an EGVII protein. In a related
embodiment, an EGVII-encoding nucleotide sequence will hybridize
under moderate to high stringency conditions to the nucleotide
sequence presented as SEQ ID NO:1.
[0166] It is appreciated that some nucleic acid sequence variants
that encode EGVII may or may not selectively hybridize to the
parent sequence. By way of example, in situations where the coding
sequence has been optimized based on the degeneracy of the genetic
code, a variant coding sequence may be produced that encodes a
EGVII protein, but does not hybridize to a native EGVII-encoding
nucleic acid sequence under moderate to high stringency conditions.
This would occur, for example, when the sequence variant includes a
different codon for each of the amino acids encoded by the parent
nucleotide.
[0167] As will be further understood by those of skill in the art,
in some cases it may be advantageous to produce nucleotide
sequences possessing non-naturally occurring codons e.g., inosine
or other non-naturally occurring nucleotide analog. Codons
preferred by a particular eukaryotic host can be selected, for
example, to increase the rate of EGVII protein expression or to
produce recombinant RNA transcripts having desirable properties,
such as a longer half-life, than transcripts produced from the
naturally occurring sequence. Hence, a native EGVII-encoding
nucleotide sequence may be engineered in order to alter the coding
sequence for a variety of reasons, including but not limited to,
alterations which modify the cloning, processing and/or expression
of the EGVII protein by a cell.
[0168] Particularly preferred are nucleic acid substitutions,
additions, and deletions that are silent such that they do not
alter the properties or activities of the native polynucleotide or
polypeptide.
[0169] The variations can be made using methods known in the art
such as oligonucleotide-mediated (site-directed) mutagenesis, and
PCR mutagenesis. Site-directed mutagenesis (Carter et al., 1986;
Zoller et al., 1987), cassette mutagenesis (Wells et al., 1985),
restriction selection mutagenesis (Wells et al., 1986) or other
known techniques can be performed on the cloned DNA to produce the
EGVII polypeptide-encoding variant DNA.
[0170] However, in some cases it may be advantageous to express
variants of eg/7 which lack the properties or activities of the
native eg/7 polynucleotide or EGVII polypeptide. In such cases,
mutant or modified forms of the native EGVII-encoding nucleic acid
sequence may be generated using techniques routinely employed by
those of skill in the art.
[0171] B. EGVII Polypeptides
[0172] In one preferred embodiment, the invention provides an EGVII
polypeptide, having a native mature or full-length EGVII
polypeptide sequence comprising the sequence presented in FIG. 2
(SEQ ID NO:2). An EGVII polypeptide of the invention can be the
mature EGVII polypeptide, part of a fusion protein or a fragment or
variant of the EGVII polypeptide sequence presented in FIG. 2 (SEQ
ID NO:2).
[0173] Ordinarily, an EGVII polypeptide of the invention has at
least 80% identity to an EGVII amino acid sequence over its entire
length. More preferable are EGVII polypeptide sequences that
comprise a region having at least 80, 85, 90, 95, 98% or more
sequence identity to the EGVII polypeptide sequence of FIG. 2 (SEQ
ID NO:2), using a sequence alignment program, as detailed
herein.
[0174] Typically, a "modified form of" a native EGVII protein or a
"variant" EGVII protein has a derivative sequence containing at
least one amino acid substitution, addition, deletion or insertion,
respectively.
[0175] It is well known in the art that certain amino acid
substitutions may be made in protein sequences without affecting
the function of the protein. Generally, conservative amino acid
substitutions or substitutions of similar amino acids are tolerated
without affecting protein function. Similar amino acids can be
those that are similar in size and/or charge properties, for
example, aspartate and glutamate, and isoleucine and valine, are
both pairs of similar amino acids. Similarity between amino acid
pairs has been assessed in the art in a number of ways. For
example, Dayhoff et al. (1978), which is incorporated by reference
herein provides frequency tables for amino acid substitutions which
can be employed as a measure of amino acid similarity. Dayhoff et
al.'s frequency tables are based on comparisons of amino acid
sequences for proteins having the same function from a variety of
evolutionarily different sources.
[0176] Fragments and variants of the EGVII polypeptide sequence of
FIG. 2 (SEQ ID NO:2), are considered to be a part of the invention.
A fragment is a variant polypeptide which has an amino acid
sequence that is entirely the same as part but not all of the amino
acid sequence of the previously described polypeptides. The
fragments can be "free-standing" or comprised within a larger
polypeptide of which the fragment forms a part or a region, most
preferably as a single continuous region. Preferred fragments are
biologically active fragments which are those fragments that
mediate activities of the polypeptides of the invention, including
those with similar activity or improved activity or with a
decreased activity. Also included are those fragments that are
antigenic or immunogenic in an animal, particularly a human. In
this aspect, the invention includes (i) fragments of EGVII,
preferably at least about 20-100 amino acids in length, more
preferably about 100-200 amino acids in length, and (ii) a
pharmaceutical composition comprising EGVII. In various
embodiments, the fragment corresponds to the N-terminal domain of
EGVII or the C-terminal domain of EGVII.
[0177] EGVII polypeptides of the invention also include
polypeptides that vary from the EGVII polypeptide sequence of FIG.
2 (SEQ ID NO:2). These variants may be substitutional, insertional
or deletional variants. The variants typically exhibit the same
qualitative biological activity as the naturally occurring
analogue, although variants can also be selected which have
modified characteristics as further described below.
[0178] A "substitution" results from the replacement of one or more
nucleotides or amino acids by different nucleotides or amino acids,
respectively.
[0179] An "insertion" or "addition" is that change in a nucleotide
or amino acid sequence which has resulted in the addition of one or
more nucleotides or amino acid residues, respectively, as compared
to the naturally occurring sequence.
[0180] A "deletion" is defined as a change in either nucleotide or
amino acid sequence in which one or more nucleotides or amino acid
residues, respectively, are absent.
[0181] Amino acid substitutions are typically of single residues;
insertions usually will be on the order of from about 1 to 20 amino
acids, although considerably larger insertions may be tolerated.
Deletions range from about 1 to about 20 residues, although in some
cases deletions may be much larger.
[0182] Substitutions, deletions, insertions or any combination
thereof may be used to arrive at a final derivative. Generally
these changes are done on a few amino adds to minimize the
alteration of the molecule. However, larger changes may be
tolerated in certain circumstances.
[0183] Amino acid substitutions can be the result of replacing one
amino acid with another amino acid having similar structural and/or
chemical properties, such as the replacement of an isoleucine with
a valine, i.e., conservative amino acid replacements. Insertions or
deletions may optionally be in the range of 1 to 5 amino acids.
[0184] Substitutions are generally made in accordance with known
"conservative substitutions". A "conservative substitution" refers
to the substitution of an amino acid in one class by an amino acid
in the same class, where a class is defined by common
physicochemical amino acid side chain properties and high
substitution frequencies in homologous proteins found in nature (as
determined, e.g., by a standard Dayhoff frequency exchange matrix
or BLOSUM matrix). (See generally, Doolittle, R. F., 1986.)
[0185] A "non-conservative substitution" refers to the substitution
of an amino add in one class with an amino acid from another
class.
[0186] EGVII polypeptide variants typically exhibit the same
qualitative biological activity as the naturally-occurring
analogue, although variants also are selected to modify the
characteristics of the EGVII polypeptide, as needed. For example,
glycosylation sites, and more particularly one or more O-linked or
N-linked glycosylation sites may be altered or removed. Those
skilled in the art will appreciate that amino acid changes may
alter post-translational processes of the EGVII polypeptide, such
as changing the number or position of glycosylation sites or
altering the membrane anchoring characteristics or secretion
characteristics or other cellular localization characteristics.
[0187] Also included within the definition of EGVII polypeptides
are other related EGVII polypeptides. Thus, probe or degenerate
polymerase chain reaction (PCR) primer sequences may be used to
find other related polypeptides. Useful probe or primer sequences
may be designed to: all or part of the EGVII polypeptide sequence,
or sequences outside the coding region. As is generally known in
the art, preferred PCR primers are from about 15 to about 35
nucleotides in length, with from about 20 to about 30 being
preferred, and may contain inosine as needed. The conditions for
the PCR reaction are generally known in the art.
[0188] Covalent modifications of EGVII polypeptides are also
included within the scope of this invention. For example, the
invention provides EGVII polypeptides that are a mature protein and
may comprise additional amino or carboxyl-terminal amino acids, or
amino acids within the mature polypeptide (for example, when the
mature form of the protein has more than one polypeptide chain).
Such sequences can, for example, play a role in the processing of
the protein from a precursor to a mature form, allow protein
transport, shorten or lengthen protein half-life, or facilitate
manipulation of the protein in assays or production.
[0189] Also contemplated are modifications directed to alteration
of an active site, alteration of the pH optima, temperature optima,
and/or substrate affinity of the EGVII enzyme.
[0190] FIG. 2 shows the predicted amino acid sequence (SEQ ID NO:2)
of an exemplary EGVII polypeptide based on the nucleotide sequence
provided in FIG. 1.
[0191] The predicted molecular weight of the encoded EGVII
polypeptide is 26.8 kDa. A predicted signal peptide of 19 amino
acids precedes the mature amino terminus of EGVII as provided in
the figure suggesting that the EGVII polypeptide is secreted
(Nielsen, H., Engelbrecht, J., Brunak, S., von Heijne, G., Protein
Engineering, 10:1-6, 1997).
[0192] A Basic BLASTP search (http://www.ncbi.nim.nih.gov/BLAST) of
the non-redundant protein database, conducted on Sep. 12, 2001 with
the EGVII amino acid sequence indicated 46% identity with GenBank
Accession Number Y11113 (endoglucanase IV of Hypocrea jecorina or
Trichoderma reesei), 41% sequence identity to GenBank Accession
Number. M86356 (cellulose-growth-specific protein of Agaricus
bisporus), and 37% sequence identity to GenBank Accession Number
AB055432 (endoglucanase B of Aspergillus kawachii). These sequence
similarities indicate that EGVII is a member of glycosyl hydrolase
family 61 (Henrissat, B. and Bairoch, A. (1993) Biochem. J.
293:781-788).
[0193] C. Anti-EGVII Antibodies.
[0194] The present invention further provides anti-EGVII
antibodies. The antibodies may be polyclonal, monoclonal,
humanized, bispecific or heteroconjugate antibodies.
[0195] Methods of preparing polyclonal antibodies are known to the
skilled artisan. The immunizing agent may be an EGVII polypeptide
or a fusion protein thereof. It may be useful to conjugate the
antigen to a protein known to be immunogenic in the mammal being
immunized. The immunization protocol may be determined by one
skilled in the art based on standard protocols or routine
experimentation.
[0196] Alternatively, the anti-EGVII antibodies may be monoclonal
antibodies. Monoclonal antibodies may be produced by cells
immunized in an animal or using recombinant DNA methods. (See,
e.g., Kohler et al., 1975; U.S. Pat. No. 4,816,567).
[0197] An anti-EGVII antibody of the invention may further comprise
a humanized or human antibody. The term "humanized antibody" refers
to humanized forms of non-human (e.g., murine) antibodies that are
chimeric antibodies, immunoglobulin chains or fragments thereof
(such as Fv, Fab, Fab', F(ab').sub.2 or other antigen-binding
partial sequences of antibodies) which contain some portion of the
sequence derived from non-human antibody. Methods for humanizing
non-human antibodies are well known in the art, as further detailed
in Jones et al., 1986; Riechmann et al., 1988; and Verhoeyen et
al., 1988. Methods for producing human antibodies are also known in
the art. See, e.g., Jakobovits, A, et al., 1995 and Jakobovits, A,
1995.
VI. Expression of Recombinant EGVII
[0198] The methods of the invention rely on the use cells to
express EGVII, with no particular method of EGVII expression
required.
[0199] The invention provides host cells which have been
transduced, transformed or transfected with an expression vector
comprising an EGVII-encoding nucleic acid sequence. The culture
conditions, such as temperature, pH and the like, are those
previously used for the parental host cell prior to transduction,
transformation or transfection and will be apparent to those
skilled in the art.
[0200] In one approach, a filamentous fungal cell or yeast cell is
transfected with an expression vector having a promoter or
biologically active promoter fragment or one or more (e.g., a
series) of enhancers which functions in the host cell line,
operably linked to a DNA segment encoding EGVII, such that EGVII is
expressed in the cell line.
[0201] A. Nucleic Acid Constructs/Expression Vectors.
[0202] Natural or synthetic polynucleotide fragments encoding EGVII
("EGVII-encoding nucleic acid sequences") may be incorporated into
heterologous nucleic acid constructs or vectors, capable of
introduction into, and replication in, a filamentous fungal or
yeast cell. The vectors and methods disclosed herein are suitable
for use in host cells for the expression of EGVII. Any vector may
be used as long as it is replicable and viable in the cells into
which it is introduced. Large numbers of suitable vectors and
promoters are known to those of skill in the art, and are
commercially available. Cloning and expression vectors are also
described in Sambrook et al., 1989, Ausubel F M et al., 1989, and
Strathern et al., 1981, each of which is expressly incorporated by
reference herein. Appropriate expression vectors for fungi are
described in van den Hondel, C. A. M. J. J. et al. (1991) In:
Bennett, J. W. and Lasure, L. L. (eds.) More Gene Manipulations in
Fungi. Academic Press, pp. 396-428. The appropriate DNA sequence
may be inserted into a plasmid or vector (collectively referred to
herein as "vectors") by a variety of procedures. In general, the
DNA sequence is inserted into an appropriate restriction
endonuclease site(s) by standard procedures. Such procedures and
related sub-cloning procedures are deemed to be within the scope of
knowledge of those skilled in the art.
[0203] Recombinant filamentous fungi comprising the coding sequence
for EGVII may be produced by introducing a heterologous nucleic
acid construct comprising the EGVII coding sequence into the cells
of a selected strain of the filamentous fungi.
[0204] Once the desired form of an eg/7 nucleic acid sequence,
homologue, variant or fragment thereof, is obtained, it may be
modified in a variety of ways. Where the sequence involves
non-coding flanking regions, the flanking regions may be subjected
to resection, mutagenesis, etc. Thus, transitions, transversions,
deletions, and insertions may be performed on the naturally
occurring sequence.
[0205] A selected eg/7 coding sequence may be inserted into a
suitable vector according to well-known recombinant techniques and
used to transform filamentous fungi capable of EGVII expression.
Due to the inherent degeneracy of the genetic code, other nucleic
acid sequences which encode substantially the same or a
functionally equivalent amino acid sequence may be used to clone
and express EGVII. Therefore it is appreciated that such
substitutions in the coding region fall within the sequence
variants covered by the present invention. Any and all of these
sequence variants can be utilized in the same way as described
herein for a parent EGVII-encoding nucleic acid sequence.
[0206] The present invention also includes recombinant nucleic acid
constructs comprising one or more of the EGVII-encoding nucleic
acid sequences as described above. The constructs comprise a
vector, such as a plasmid or viral vector, into which a sequence of
the invention has been inserted, in a forward or reverse
orientation.
[0207] Heterologous nucleic acid constructs may include the coding
sequence for eg/7, or a variant, fragment or splice variant
thereof: (i) in isolation; (ii) in combination with additional
coding sequences; such as fusion protein or signal peptide coding
sequences, where the eg/7 coding sequence is the dominant coding
sequence; (iii) in combination with non-coding sequences, such as
introns and control elements, such as promoter and terminator
elements or 5' and/or 3' untranslated regions, effective for
expression of the coding sequence in a suitable host; and/or (iv)
in a vector or host environment in which the eg/7 coding sequence
is a heterologous gene.
[0208] In one aspect of the present invention, a heterologous
nucleic acid construct is employed to transfer an EGVII-encoding
nucleic acid sequence into a cell in vitro, with established
filamentous fungal and yeast lines preferred. For long-term,
high-yield production of EGVII, stable expression is preferred. It
follows that any method effective to generate stable transformants
may be used in practicing the invention.
[0209] Appropriate vectors are typically equipped with a selectable
marker-encoding nucleic acid sequence, insertion sites, and
suitable control elements, such as promoter and termination
sequences. The vector may comprise regulatory sequences, including,
for example, non-coding sequences, such as introns and control
elements, i.e., promoter and terminator elements or 5' and/or 3'
untranslated regions, effective for expression of the coding
sequence in host cells (and/or in a vector or host cell environment
in which a modified soluble protein antigen coding sequence is not
normally expressed), operably linked to the coding sequence. Large
numbers of suitable vectors and promoters are known to those of
skill in the art, many of which are commercially available and/or
are described in Sambrook, et al., (supra).
[0210] Exemplary promoters include both constitutive promoters and
inducible promoters, examples of which include a CMV promoter, an
SV40 early promoter, an RSV promoter, an EF-1.alpha. promoter, a
promoter containing the tet responsive element (TRE) in the tet-on
or tet-off system as described (ClonTech and BASF), the beta actin
promoter and the metallothionine promoter that can upregulated by
addition of certain metal salts. A promoter sequence is a DNA
sequence which is recognized by the particular filamentous fungus
for expression purposes. It is operably linked to DNA sequence
encoding an EGVII polypeptide. Such linkage comprises positioning
of the promoter with respect to the initiation codon of the DNA
sequence encoding the EGVII polypeptide in the disclosed expression
vectors. The promoter sequence contains transcription and
translation control sequence which mediate the expression of the
EGVII polypeptide. Examples include the promoters from the
Aspergillus niger, A awamori or A. oryzae glucoamylase,
alpha-amylase, or alpha-glucosidase encoding genes; the A. nidulans
gpdA or trpC Genes; the Neurospora crassa cbh1 or trp1 genes; the
A. niger or Rhizomucor miehei aspartic proteinase encoding genes;
the T. reesei cbh1, cbh2, eg/1, eg/2, or other cellulase encoding
genes.
[0211] The choice of the proper selectable marker will depend on
the host cell, and appropriate markers for different hosts are well
known in the art. Typical selectable marker genes include argB from
A. nidulans or T. reesei, amdS from A. nidulans, pyr4 from
Neurospora crassa or T. reesei, pyrG from Aspergillus niger or A.
nidulans. Additional exemplary selectable markers include, but are
not limited to trpc, trp1, oliC31, niaD or leu2, which are included
in heterologous nucleic acid constructs used to transform a mutant
strain such as trp-, pyr-, leu- and the like.
[0212] Such selectable markers confer to transformants the ability
to utilize a metabolite that is usually not metabolized by the
filamentous fungi. For example, the amdS gene from T. reesei which
encodes the enzyme acetamidase that allows transformant cells to
grow on acetamide as a nitrogen source. The selectable marker (e.g.
pyrG) may restore the ability of an auxotrophic mutant strain to
grow on a selective minimal medium or the selectable marker (e.g.
olic31) may confer to transformants the ability to grow in the
presence of an inhibitory drug or antibiotic.
[0213] The selectable marker coding sequence is cloned into any
suitable plasmid using methods generally employed in the art.
Exemplary plasmids include pUC18, pBR322, and pUC100.
[0214] The practice of the present invention will employ, unless
otherwise indicated, conventional techniques of molecular biology,
microbiology, recombinant DNA, and immunology, which are within the
skill of the art. Such techniques are explained fully in the
literature. See, for example, Sambrook et al., 1989; Freshney,
1987; Ausubel, et al., 1993; and Coligan et al., 1991. All patents,
patent applications, articles and publications mentioned herein,
are hereby expressly incorporated herein by reference.
[0215] B. Host Cells and Culture Conditions for Enhanced EGVII
Production
[0216] (i) Filamentous Fungi
[0217] Thus, the present invention provides filamentous fungi
comprising cells which have been modified, selected and cultured in
a manner effective to result in enhanced EGVII production or
expression relative to the corresponding non-transformed parental
fungi.
[0218] Examples of species of parental filamentous fungi that may
be treated and/or modified for enhanced EGVII expression include,
but are not limited to Trichoderma, e.g., Trichoderma reesei,
Trichoderma longibrachiatum, Trichoderma viride, Trichoderma
koningii; Penicillium sp., Humicola sp., including Humicola
insolens; Aspergillus sp., Chrysosporium sp., Fusarium sp.,
Hypocrea sp., and Emericella sp.
[0219] EGVII expressing cells are cultured under conditions
typically employed to culture the parental fungal line. Generally,
cells are cultured in a standard medium containing physiological
salts and nutrients, such as described in Pourquie, J. et al.,
Biochemistry and Genetics of Cellulose Degradation, eds. Aubert, J.
P. et al., Academic Press, pp. 71-86, 1988 and Ilmen, M. et al.,
Appl. Environ. Microbiol. 63:1298-1306, 1997. Culture conditions
are also standard, e.g., cultures are incubated at 28.degree. C. in
shaker cultures or fermenters until desired levels of EGVII
expression are achieved.
[0220] Preferred culture conditions for a given filamentous fungus
may be found in the scientific literature and/or from the source of
the fungi such as the American Type Culture Collection (ATCC;
"http://www.atcc.org/"). After fungal growth has been established,
the cells are exposed to conditions effective to cause or permit
the over expression of EGVII.
[0221] In cases where an EGVII coding sequence is under the control
of an inducible promoter, the inducing agent, e.g., a sugar, metal
salt or antibiotics, is added to the medium at a concentration
effective to induce high-level EGVII expression.
[0222] (ii) Yeast
[0223] The present invention also contemplates the use of yeast as
a host cell for EGVII production. Several other genes encoding
hydrolytic enzymes have been expressed in various strains of the
yeast S. cerevisiae. These include sequences encoding for two
endoglucanases (Penttila et al., 1987), two cellobiohydrolases
(Penttila et al., 1988) and one beta-glucosidase from Trichoderma
reesei (Cummings and Fowler, 1996), a xylanase from Aureobasidlium
pullulans (Li and Ljungdahl, 1996), an alpha-amylase from wheat
(Rothstein et al., 1987), etc. In addition, a cellulase gene
cassette encoding the Butyrivibrio fibrisolvens
endo-[beta]-1,4-glucanase (END1), Phanerochaete chrysosporium
cellobiohydrolase (CBH1), the Ruminococcus flavefaciens
cellodextrinase (CEL1) and the Endomyces fibrilizer cellobiase
(Bgl1) was successfully expressed in a laboratory strain of S.
cerevisiae (Van Rensburg et al., 1998).
[0224] C. Introduction of an EGVII-Encoding Nucleic Acid Sequence
into Host Cells.
[0225] The invention further provides cells and cell compositions
which have been genetically modified to comprise an exogenously
provided EGVII-encoding nucleic acid sequence. A parental cell or
cell line may be genetically modified (i.e., transduced,
transformed or transfected) with a cloning vector or an expression
vector. The vector may be, for example, in the form of a plasmid, a
viral particle, a phage, etc, as further described above.
[0226] Various methods may be employed for delivering an expression
vector into cells in vitro. After a suitable vector is constructed,
it is used to transform strains of fungi or yeast. General methods
of introducing nucleic acids into cells for expression of
heterologous nucleic acid sequences are known to the ordinarily
skilled artisan. Such methods include, but not limited to,
electroporation; nuclear microinjection or direct microinjection
into single cells; bacterial protoplast fusion with intact cells;
use of polycations, e.g., polybrene or polyornithine; membrane
fusion with liposomes, lipofectamine or lipofection-mediated
transfection; high velocity bombardment with DNA-coated
microprojectiles; incubation with calcium phosphate-DNA
precipitate; DEAE-Dextran mediated transfection; infection with
modified viral nucleic acids; and the like.
[0227] Preferred methods for introducing a heterologous nucleic
acid construct (expression vector) into filamentous fungi (e.g., T.
reesei) include, but are not limited to the use of a particle or
gene gun, permeabilization of filamentous fungi cells walls prior
to the transformation process (e.g., by use of high concentrations
of alkali, e.g., 0.05 M to 0.4 M CaCl.sub.2 or lithium acetate),
protoplast fusion or agrobacterium mediated transformation. An
exemplary method for transformation of filamentous fungi by
treatment of protoplasts or spheroplasts with polyethylene glycol
and CaCl.sub.2 is described in Campbell, E. I. et al., Curr. Genet.
16:53-56, 1989 and Penttila, M. et al., Gene, 63:11-22, 1988.
[0228] In addition, heterologous nucleic acid constructs comprising
an EGVII-encoding nucleic acid sequence can be transcribed in
vitro, and the resulting RNA introduced into the host cell by
well-known methods, e.g., by injection.
[0229] Following introduction of a heterologous nucleic acid
construct comprising the coding sequence for eg/7, the genetically
modified cells can be cultured in conventional nutrient media
modified as appropriate for activating promoters, selecting
transformants or amplifying expression of an EGVII-encoding nucleic
acid sequence. The culture conditions, such as temperature, pH and
the like, are those previously used for the host cell selected for
expression, and will be apparent to those skilled in the art.
[0230] The progeny of cells into which such heterologous nucleic
acid constructs have been introduced are generally considered to
comprise the EGVII-encoding nucleic acid sequence found in the
heterologous nucleic acid construct.
[0231] The invention further includes novel and useful
transformants of filamentous fungi such as Trichoderma reesei for
use in producing fungal cellulase compositions. The invention
includes transformants of filamentous fungi especially fungi
comprising the eg/7 coding sequence, comprising a modified form of
the eg/7 coding sequence or deletion of the eg/7 coding
sequence.
[0232] Stable transformants of filamentous fungi can generally be
distinguished from unstable transformants by their faster growth
rate and the formation of circular colonies with a smooth rather
than ragged outline on solid culture medium. Additionally, in some
cases, a further test of stability can be made by growing the
transformants on solid non-selective medium, harvesting the spores
from this culture medium and determining the percentage of these
spores which will subsequently germinate and grow on selective
medium.
VII. Analysis For EGVII Nucleic Acid Coding Sequences and/or
Protein Expression.
[0233] In order to evaluate the expression of EGVII by a cell line
that has been transformed with an EGVII-encoding nucleic acid
construct, assays can be carried out at the protein level, the RNA
level or by use of functional bioassays particular to endoglucanase
activity and/or production.
[0234] In one exemplary application of the eg/7 nucleic acid and
protein sequences described herein, a genetically modified strain
of filamentous fungi, e.g., Trichoderma reesei, is engineered to
produce an increased amount of EGVII. Such genetically modified
filamentous fungi would be useful to produce a cellulase product
with greater increased cellulolytic capacity. In one approach, this
is accomplished by introducing the coding sequence for eg/7 into a
suitable host, e.g., a filamentous fungi such as Trichoderma
reesei.
[0235] Accordingly, the invention includes methods for expressing
EGVII in a filamentous fungus or other suitable host by introducing
an expression vector containing the DNA sequence encoding EGVII
into cells of the filamentous fungus or other suitable host.
[0236] In another aspect, the invention includes methods for
modifying the expression of EGVII in a filamentous fungus or other
suitable host. Such modification includes a decrease or elimination
in expression, or expression of an altered form of EGVII. An
altered form of EGVII may have an altered amino acid sequence or an
altered nucleic acid sequence.
[0237] In general, assays employed to analyze the expression of
EGVII include, Northern blotting, dot blotting (DNA or RNA
analysis), RT-PCR (reverse transcriptase polymerase chain
reaction), or in situ hybridization, using an appropriately labeled
probe (based on the nucleic acid coding sequence) and conventional
Southern blotting and autoradiography.
[0238] In addition, the production and/or expression of EGVII may
be measured in a sample directly, for example, by assays for
endoglucanase activity, expression and/or production. Such assays
are described, for example, in Shoemaker, S. P. and Brown, R. D.
Jr. (Biochim. Biophys. Acta, 1978, 523:133-146; Schulein (1988) and
U.S. Pat. Nos. 5,246,853 and 5,475,101 each of which is expressly
incorporated by reference herein. The ability of EGVII to hydrolyze
isolated soluble and insoluble substrates can be measured using
assays described in Suumakki et al. (2000) and Ortega et al.
(2001). Substrates useful for assaying cellobiohydrolase,
endoglucanase or .beta.-glucosidase activities include crystalline
cellulose, filter paper, phosphoric acid swollen cellulose,
hydroxyethyl cellulose, carboxymethyl cellulose,
cellooligosaccharides, methylumbelliferyl lactoside,
methylumbelliferyl cellobioside, orthonitrophenyl lactoside,
paranitrophenyl lactoside, orthonitrophenyl cellobioside,
paranitrophenyl cellobioside, orthonitrophenyl glucoside,
paranitrophenyl glucoside, methylumbelliferyl glycoside
[0239] In addition, protein expression, may be evaluated by
immunological methods, such as immunohistochemical staining of
cells, tissue sections or immunoassay of tissue culture medium,
e.g., by Western blot or ELISA. Such immunoassays can be used to
qualitatively and quantitatively evaluate expression of EGVII. The
details of such methods are known to those of skill in the art and
many reagents for practicing such methods are commercially
available.
[0240] A purified form of EGVII may be used to produce either
monoclonal or polyclonal antibodies specific to the expressed
protein for use in various immunoassays. (See, e.g., Hu et al.,
1991). Exemplary assays include ELISA, competitive immunoassays,
radioimmunoassays, Western blot, indirect immunofluorescent assays
and the like. In general, commercially available antibodies and/or
kits may be used for the quantitative immunoassay of the expression
level of endoglucanase proteins.
VII. Isolation and Purification of Recombinant EGVII Protein.
[0241] In general, an EGVII protein produced in cell culture is
secreted into the medium and may be purified or isolated, e.g., by
removing unwanted components from the cell culture medium. However,
in some cases, an EGVII protein may be produced in a cellular form
necessitating recovery from a cell lysate. In such cases the EGVII
protein is purified from the cells in which it was produced using
techniques routinely employed by those of skill in the art.
Examples include, but are not limited to, affinity chromatography
(Tilbeurgh et al., 1984), ion-exchange chromatographic methods
(Goyal et al., 1991; Fliess et al., 1983; Bhikhabhai et al., 1984;
Ellouz et al., 1987), including ion-exchange using materials with
high resolution power (Medve et al., 1998), hydrophobic interaction
chromatography (Tomaz and Queiroz, 1999), and two-phase
partitioning (Brumbauer, et al., 1999).
[0242] Typically, the EGVII protein is fractionated to segregate
proteins having selected properties, such as binding affinity to
particular binding agents, e.g., antibodies or receptors; or which
have a selected molecular weight range, or range of isoelectric
points.
[0243] Once expression of a given EGVII protein is achieved, the
EGVII protein thereby produced is purified from the cells or cell
culture. Exemplary procedures suitable for such purification
include the following: antibody-affinity column chromatography, ion
exchange chromatography; ethanol precipitation; reverse phase HPLC;
chromatography on silica or on a cation-exchange resin such as
DEAE; chromatofocusing; SDS-PAGE; ammonium sulfate precipitation;
and gel filtration using, e.g., Sephadex G-75. Various methods of
protein purification may be employed and such methods are known in
the art and described e.g. in Deutscher, 1990; Scopes, 1982. The
purification step(s) selected will depend, e.g., on the nature of
the production process used and the particular protein
produced.
IX. Utility of eg/7 and EGVII
[0244] It can be appreciated that the eg/7 nucleotide, the EGVII
protein and compositions comprising EGVII protein activity find
utility in a wide variety applications, some of which are described
below.
[0245] New and improved cellulase compositions that comprise
varying amounts CBH-type, EG-type and BG-type cellulases find
utility in detergent compositions that exhibit enhanced cleaning
ability, function as a softening agent and/or improve the feel of
cotton fabrics (e.g., "stone washing" or "biopolishing"), in
compositions for degrading wood pulp into sugars (e.g., for
bio-ethanol production), and/or in feed compositions. The isolation
and characterization of cellulase of each type provides the ability
to control the aspects of such compositions.
[0246] In one preferred approach, the cellulase of the invention
finds utility in detergent compositions or in the treatment of
fabrics to improve the feel and appearance.
[0247] Since the rate of hydrolysis of cellulosic products may be
increased by using a transformant having at least one additional
copy of the eg/7 gene inserted into the genome, products that
contain cellulose or heteroglycans can be degraded at a faster rate
and to a greater extent. Products made from cellulose such as
paper, cotton, cellulosic diapers and the like can be degraded more
efficiently in a landfill. Thus, the fermentation product
obtainable from the transformants or the transformants alone may be
used in compositions to help degrade by liquefaction a variety of
cellulose products that add to the overcrowded landfills.
[0248] Separate saccharification and fermentation is a process
whereby cellulose present in biomass, e.g., corn stover, is
converted to glucose and subsequently yeast strains convert glucose
into ethanol. Simultaneous saccharification and fermentation is a
process whereby cellulose present in biomass, e.g., corn stover, is
converted to glucose and, at the same time and in the same reactor,
yeast strains convert glucose into ethanol. Thus, in another
preferred approach, the glucosidase type cellulase of the invention
finds utility in the degradation of biomass to ethanol. Ethanol
production from readily available sources of cellulose provides a
stable, renewable fuel source.
[0249] Cellulose-based feedstocks are comprised of agricultural
wastes, grasses and woods and other low-value biomass such as
municipal waste (e.g., recycled paper, yard clippings, etc.).
Ethanol may be produced from the fermentation of any of these
cellulosic feedstocks. However, the cellulose must first be
converted to sugars before there can be conversion to ethanol.
[0250] A large variety of feedstocks may be used with the inventive
endoglucanase and the one selected for use may depend on the region
where the conversion is being done. For example, in the Midwestern
United States agricultural wastes such as wheat straw, corn stover
and bagasse may predominate while in California rice straw may
predominate. However, it should be understood that any available
cellulosic biomass may be used in any region.
[0251] A cellulase composition containing an enhanced amount of
endoglucanase finds utility in ethanol production. Ethanol from
this process can be further used as an octane enhancer or directly
as a fuel in lieu of gasoline which is advantageous because ethanol
as a fuel source is more environmentally friendly than petroleum
derived products. It is known that the use of ethanol will improve
air quality and possibly reduce local ozone levels and smog.
Moreover, utilization of ethanol in lieu of gasoline can be of
strategic importance in buffering the impact of sudden shifts in
non-renewable energy and petrochemical supplies.
[0252] Ethanol can be produced via saccharification and
fermentation processes from cellulosic biomass such as trees,
herbaceous plants, municipal solid waste and agricultural and
forestry residues. However, the ratio of individual cellulase
enzymes within a naturally occurring cellulase mixture produced by
a microbe may not be the most efficient for rapid conversion of
cellulose in biomass to glucose. It is known that endoglucanases
act to produce new cellulose chain ends which themselves are
substrates for the action of cellobiohydrolases and thereby improve
the efficiency of hydrolysis of the entire cellulase system.
Therefore, the use of increased or optimized endoglucanase activity
would greatly enhance the production of ethanol.
[0253] Thus, the inventive endoglucanase finds use in the
hydrolysis of cellulose to its sugar components. In one embodiment,
the endoglucanase is added to the biomass prior to the addition of
a fermentative organism. In a second embodiment, the endoglucanase
is added to the biomass at the same time as a fermentative
organism. Optionally, there may be other cellulase components
present in either embodiment.
[0254] In another embodiment the cellulosic feedstock may be
pretreated. Pretreatment may be by elevated temperature and the
addition of either of dilute acid, concentrated acid or dilute
alkali solution. The pretreatment solution is added for a time
sufficient to at least partially hydrolyze the hemicellulose
components and then neutralized.
[0255] In an alternative approach, a cellulase composition which is
deficient in or free of endoglucanase is preferred. The deletion of
the endoglucanase gene of this invention would be particularly
useful in preparing cellulase compositions for use in detergents.
Additionally, such compositions are useful for the production of
cellooligosaccharides. The deletion of the eg/7 gene from T. reesei
strains would be particularly useful in preparing cellulase
compositions for use in the detergents and in
isolatingcellooligosaccharides. The cellulase enzymes have been
used in a variety of detergent compositions to enzymatically clean
clothes. However, it is known in this art that use of cellulase
enzymes can impart degradation of the cellulose fibers in clothes.
One possibility to decrease the degradation effect is to produce a
detergent that does not containendoglucanase. Thus, the deletion of
this protein would effect the cellulase system to inhibit the other
components via accumulation of cellobiose. The modified
microorganisms of this invention are particularly suitable for
preparing such compositions because the eg/7 gene can be deleted
leaving the remaining CBH and EG components resulting in improved
cleaning and softening benefits in the composition without
degradative effects.
[0256] The detergent compositions of this invention may employ
besides the cellulase composition (irrespective of the
endoglucanase content, i.e., endoglucanase-free, substantially
endoglucanase-free, or endoglucanase enhanced), a surfactant,
including anionic, non-ionic and ampholytic surfactants, a
hydrolase, building agents, bleaching agents, bluing agents and
fluorescent dyes, caking inhibitors, solubilizers, cationic
surfactants and the like. All of these components are known in the
detergent art. The cellulase composition as described above can be
added to the detergent composition either in a liquid diluent, in
granules, in emulsions, in gels, in pastes, and the like. Such
forms are well known to the skilled artisan. When a solid detergent
composition is employed, the cellulase composition is preferably
formulated as granules. Preferably, the granules can be formulated
so as to contain a cellulase protecting agent. For a more thorough
discussion, see U.S. Pat. No. 6,162,782 entitled "Detergent
compositions containing cellulase compositions deficient in CBH I
type components," which is incorporated herein by reference.
[0257] In yet another embodiment, the detergent compositions can
also contain enhanced levels of endoglucanase or altered
endoglucanase. In this regard, it really depends upon the type of
product one desires to use in detergent compositions to give the
appropriate effects.
[0258] Preferably the cellulase compositions are employed from
about 0.00005 weight percent to about 5 weight percent relative to
the total detergent composition. More preferably, the cellulase
compositions are employed from about 0.0002 weight percent to about
2 weight percent relative to the total detergent composition.
[0259] Portions of the eg/7 nucleic acid sequence that are capable
of binding to cellulose can be used to generate bacterial chimeric
surface proteins, allowing whole-cell immobilization onto cellulose
filters or other fibrous solid supports as described in Lehtio et
al., 2001.
[0260] In addition the eg/7 nucleic acid sequence finds utility in
the identification and characterization of related nucleic acid
sequences. A number of techniques useful for determining
(predicting or confirming) the function of related genes or gene
products include, but are not limited to, (A) DNA/RNA analysis,
such as (1) overexpression, ectopic expression, and expression in
other species; (2) gene knock-out (reverse genetics, targeted
knockout, viral induced gene silencing (VIGS, see Baulcombe, 1999);
(3) analysis of the methylation status of the gene, especially
flanking regulatory regions; and (4) in situ hybridization; (B)
gene product analysis such as (1) recombinant protein expression;
(2) antisera production, (3) immunolocalization; (4) biochemical
assays for catalytic or other activity; (5) phosphorylation status;
and (6) interaction with other proteins via yeast two-hybrid
analysis; (C) pathway analysis, such as placing a gene or gene
product within a particular biochemical or signaling pathway based
on its overexpression phenotype or by sequence homology with
related genes; and (D) other analyses which may also be performed
to determine or confirm the participation of the isolated gene and
its product in a particular metabolic or signaling pathway, and
help determine gene function.
[0261] Endoglucanases and beta-glucosidases may be responsible for
the production of disaccharides, such as sophorose, from
cellooligosaccharides and glucose by transglycosylation reactions.
Sophorose is known to be a very potent inducer of cellulase gene
expression (Ilmen, M. et al., 1997, Appl. Environ. Microbiol.
63:1298-1306 and references therein). In this way EGs and BGLs may
play an important role in the process of induction of cellulase
gene expression. Over-expression of certain EGs or BGLs in a fungal
strain may lead to higher overall cellulase productivity by that
strain.
[0262] A. Homology Known Sequences
[0263] The function of a related EGVII-encoding nucleic acid
sequence may be determined by homology to known genes having a
particular function. For example, a comparison of the coding
sequence of an identified nucleic acid molecule to public nucleic
acid sequence databases is used to confirm function by homology to
known genes or by extension of the identified nucleic acid
sequence.
[0264] The term "% homology" is used interchangeably herein with
the term "% identity" herein and refers to the level of nucleic
acid or amino acid sequence identity between the nucleic acid
sequence that encodes EGVII or the EGVII amino acid sequence, when
aligned using a sequence alignment program.
[0265] For example, as used herein, 80% homology means the same
thing as 80% sequence identity determined by a defined algorithm,
and accordingly a homologue of a given sequence has greater than
80% sequence identity over a length of the given sequence.
Exemplary levels of sequence identity include, but are not limited
to, 80, 85, 90, 95, 98% or more sequence identity to a given
sequence, e.g., the coding sequence for eg/7, as described
herein.
[0266] Exemplary computer programs which can be used to determine
identity between two sequences include, but are not limited to, the
suite of BLAST programs, e.g., BLASTN, BLASTX, and TBLASTX, BLASTP
and TBLASTN, publicly available on the Internet at
http://www.ncbi.nlm.nih.gov/BLAST/. See also, Altschul, et al.,
1990 and Altschul, et al., 1997.
[0267] Sequence searches are typically carried out using the BLASTN
program when evaluating a given nucleic acid sequence relative to
nucleic acid sequences in the GenBank DNA Sequences and other
public databases. The BLASTX program is preferred for searching
nucleic acid sequences that have been translated in all reading
frames against amino acid sequences in the GenBank Protein
Sequences and other public databases. Both BLASTN and BLASTX are
run using default parameters of an open gap penalty of 11.0, and an
extended gap penalty of 1.0, and utilize the BLOSUM-62 matrix.
(See, e.g., Altschul, et al., 1997.)
[0268] A preferred alignment of selected sequences in order to
determine "% identity" between two or more sequences, is performed
using for example, the CLUSTAL-W program in MacVector version 6.5,
operated with default parameters, including an open gap penalty of
10.0, an extended gap penalty of 0.1, and a BLOSUM 30 similarity
matrix.
[0269] In one exemplary approach, sequence extension of a nucleic
acid encoding eg/7 may be carried out using conventional primer
extension procedures as described in Sambrook et al., supra, to
detect eg/7 precursors and processing intermediates of mRNA that
may not have been reverse-transcribed into cDNA and/or to identify
ORFs that encode a full length protein.
[0270] In yet another aspect, the present invention includes the
entire or partial nucleotide sequence of the nucleic acid sequence
of eg/7 for use as a probe. Such a probe may be used to identify
and clone out homologous nucleic acid sequences from related
organisms.
[0271] Screening of a cDNA or genomic library with the selected
probe may be conducted using standard procedures, such as described
in Sambrook et al., (1989). Hybridization conditions, including
moderate stringency and high stringency, are provided in Sambrook
et al., supra.
[0272] The probes or portions thereof may also be employed in PCR
techniques to generate a pool of sequences for identification of
closely related eg/7 sequences. When eg/7 sequences are intended
for use as probes, a particular portion of an EGVII encoding
sequence, for example a highly conserved portion of the coding
sequence may be used.
[0273] For example, an eg/7 nucleotide sequence may be used as a
hybridization probe for a cDNA library to isolate genes, for
example, those encoding naturally-occurring variants of EGVII from
other fungal, bacterial or plant species, which have a desired
level of sequence identity to the eg/7 nucleotide sequence
disclosed in FIG. 1 (SEQ ID NO:1). Exemplary probes have a length
of about 20 to about 50 bases.
[0274] B. Two Hybrid Analysis
[0275] Proteins identified by the present invention can be used in
the yeast two-hybrid system to "capture" protein binding proteins
which are putative signal pathway proteins. The yeast two hybrid
system is described in Fields and Song, Nature 340:245-246 (1989).
Briefly, in a two-hybrid system, a fusion of a DNA-binding
domain-eg/7 (e.g., GAL4-eg/7 fusion) is constructed and transfected
into yeast cells. The whole eg/7 gene, or subregions of the eg/7
gene, may be used. A second construct containing the library of
potential binding partners fused to the DNA activation domain is
co-transfected. Yeast co-transformants harboring proteins that bind
to the EGVII protein are identified by, for example,
beta-galactosidase or luciferase production (a screen), or survival
on plates lacking an essential nutrient (a selection), as
appropriate for the vectors used.
[0276] C. Microarray Analysis
[0277] In addition, microarray analysis, also known as expression
profiling or transcript profiling, may be used to simultaneously
evaluate the presence or expression of given DNA sequences, or
changes in the expression of many different genes. In one approach,
a large set of DNA sequences (probes), usually a broad set of
expressed sequence tags, cDNAs, cDNA fragments, or
sequence-specific oligonucleotides, is arrayed on a solid support
such as a glass slide or nylon membrane. Labelled target for
hybridization to the probes is generated by isolating mRNA from
control and induced tissue, then labeling each mRNA pool either
directly or via a cDNA or cRNA intermediate, with a distinct
marker, usually a fluorescent dye. The microarray is hybridized
with the complex probes, and the relative hybridization signal
intensity associated with each location on the array can be
quantitated for each marker dye. Differences in expression between
the control and induced states can be measured as a ratio of the
signal from the two marker dyes. (See Baldwin, D et al., 1999.)
[0278] Microarray analysis of the source organism from which eg/7
was derived may be carried out, to facilitate the understanding of
gene function by identifying other genes that are coordinately
regulated as a consequence of the overexpression of eg/7. The
identity of coordinately regulated genes may help to place the eg/7
gene in a particular pathway. Alternatively, such analysis may be
used to identify other genes involved in the same pathway using
microarray analysis.
[0279] All publications, patents and patent applications are herein
expressly incorporated by reference in their entirety.
[0280] While the invention has been described with reference to
specific methods and embodiments, it will be appreciated that
various modifications and changes may be made without departing
from the invention.
EXAMPLE 1
[0281] In one exemplary approach, a cDNA fragment for use as a
probe is isolated by extracting total RNA from mycelia of a T.
reesei strain grown under conditions known to induce cellulase
production and obtaining the polyadenylated (polyA) fraction
therefrom. The polyA RNA is used to produce a cDNA pool which is
then amplified using specific primers based on the eg/7 nucleic
acid sequence provided herein.
[0282] Total RNA is isolated from the mycelia using methods known
in the art, for example as described in Timberlake et al., 1981;
Maniatis, et al., 1989; Ausubel, et al., 1993 and Sambrook et al.,
1989, each of which is expressly incorporated by reference herein.
Once isolated, Northern blots are performed to confirm cellulase
expression and select an optimal induction time for cellulase
expression and corresponding RNA isolation.
[0283] Messenger RNA (mRNA), having a poly (A) tail at the 3' end,
may be purified from total RNA using methods known in the art.
[0284] The T. reesei RNA is used as template for RT-PCR using
methods known in the art (Loftus, J. et al., Science, 249:915-918,
1990). During this procedure the mRNA is reverse transcribed to
produce first strand cDNA. The cDNA subsequently serves as template
for PCR amplification of eg/7 cDNA sequences using specific
olionucleotide primers designed in accordance with SEQ ID No. 1 or
SEQ ID No. 4. TABLE-US-00001 TABLE 1 Sequences Provided in Support
Of The Invention. SEQ. Description ID NO. full length T. reesei
egl7 cDNA nucleic 1 acid sequence
ATTTAAGGATCTAAGCCCCATCGATATGAAGTCCTGCGCCATT
CTTGCAGCCCTTGGCTGTCTTGCCGGGAGCGTTCTCGGCCATG
GACAAGTCCAAAACTTCACGATCAATGGACAATACAATCAGGG
TTTCATTCTCGATTACTACTATCAGAAGCAGAATACTGGTCAC
TTCCCCAACGTTGCTGGCTGGTACGCCGAGGACCTAGACCTGG
GCTTCATCTCCCCTGACCAATACACCACGCCCGACATTGTCTG
TCACAAGAACGCGGCCCCAGGTGCCATTTCTGCCACTGCAGCG
GCCGGCAGCAACATCGTCTTCCAATGGGGCCCTGGCGTCTGGC
CTCACCCCTACGGTCCCATCGTTACCTACGTGGTTGAGTGCAG
CGGATCGTGCACGACCGTGAACAAGAACAACCTGCGCTGGGTC
AAGATTCAGGAGGCCGGCATCAACTATAACACCCAAGTCTGGG
CGCAGCAGGATCTGATCAACCAGGGCAACAAGTGGACTGTGAA
GATCCCGTCGAGCCTCAGGCCCGGAAACTATGTCTTCCGCCAT
GAACTTCTTGCTGCCCATGGTGCCTCTAGTGCGAACGGCATGC
AGAACTATCCTCAGTGCGTGAACATCGCCGTCACAGGCTCGGG
CACGAAAGCGCTCCCTGCCGGAACTCCTGCAACTCAGCTTTAC
AAGCCCACTGACCCTGGCATCTTGTTCAACCCTTACACAACAA
TCACGAGCTACACCATCCCTGGCCCAGCCCTGTGGCAAGGCTA
GATCCAGGGGTACGGTGTTGGCGTTCGTGAAGTCGGAGCTGTT
GACAAGGATATCTGATGATGAACGGAGAGGACTGATGGGCGTG
ACTGAGTGTATATATTTTTGATGACCAAATTGTATACGAAATC
CGAACGCATGGTGATCATTGTTTATCCCTGTAGTATATTGTCT
CCAGGCTGCTAAGAGCCCACGGGTGTATTACGGCAACAAAGTC
AGGAATTTGGGTGGCAAAAAAAAAAAAAAAAAAAAAAAAAAAA AAAAAAAAAAAAAAA T.
reesei EGVII predicted amino acid 2 sequence
HGQVQNFTINGQYNQGFILDYYYQKQNTGHFPNVAGWYAEDLD
LGFISPDQYTTPDIVCHKNAAPGAISATAAAGSNIVFQWGPGV
WPHPYGPIVTYVVECSGSCTTVNKNNLRWVKIQEAGINYNTQV
WAQQDLINQGNKWTVKIPSSLRPGNYVFRHELLAAHGASSANG
MQNYPQCVNIAVTGSGTKALPAGTPATQLYKPTDPGILFNPYT TITSYTIPGPALWQG T.
reesei EGVII protein predicted signal 3 sequence:
MKSCAILAALGCLAGSVLG T. reesei egl7 nucleic acid coding sequence 4
ATGAAGTCCTGCGCCATTCTTGCAGCCCTTGGCTGTCTTGCCG
GGAGCGTTCTCGGCCATGGACAAGTCCAAAACTTCACGATCAA
TGGACAATACAATCAGGGTTTCATTCTCGATTACTACTATCAG
AAGCAGAATACTGGTCACTTCCCCAACGTTGCTGGCTGGTACG
CCGAGGACCTAGACCTGGGCTTCATCTCCCCTGACCAATACAC
CACGCCCGACATTGTCTGTCACAAGAACGCGGCCCCAGGTGCC
ATTTCTGCCACTGCAGCGGCCGGCAGCAACATCGTCTTCCAAT
GGGGCCCTGGCGTCTGGCCTCACCCCTACGGTCCCATCGTTAC
CTACGTGGTTGAGTGCAGCGGATCGTGCACGACCGTGAACAAG
AACAACCTGCGCTGGGTCAAGATTCAGGAGGCCGGCATCAACT
ATAACACCCAAGTCTGGGCGCAGCAGGATCTGATCAACCAGGG
CAACAAGTGGACTGTGAAGATCCCGTCGAGCCTCAGGCCCGGA
AACTATGTCTTCCGCCATGAACTTCTTGCTGCCCATGGTGCCT
CTAGTGCGAACGGCATGCAGAACTATCCTCAGTGCGTGAACAT
CGCCGTCACAGGCTCGGGCACGAAAGCGCTCCCTGCCGGAACT
CCTGCAACTCAGCTTTACAAGCCCACTGACCCTGGCATCTTGT
TCAACCCTTACACAACAATCACGAGCTACACCATCCCTGGCCC AGCCCTGTGGCAAGGCTAG
[0285]
Sequence CWU 1
1
4 1 1047 DNA Trichoderma reesei 1 atttaaggat ctaagcccca tcgatatgaa
gtcctgcgcc attcttgcag cccttggctg 60 tcttgccggg agcgttctcg
gccatggaca agtccaaaac ttcacgatca atggacaata 120 caatcagggt
ttcattctcg attactacta tcagaagcag aatactggtc acttccccaa 180
cgttgctggc tggtacgccg aggacctaga cctgggcttc atctcccctg accaatacac
240 cacgcccgac attgtctgtc acaagaacgc ggccccaggt gccatttctg
ccactgcagc 300 ggccggcagc aacatcgtct tccaatgggg ccctggcgtc
tggcctcacc cctacggtcc 360 catcgttacc tacgtggttg agtgcagcgg
atcgtgcacg accgtgaaca agaacaacct 420 gcgctgggtc aagattcagg
aggccggcat caactataac acccaagtct gggcgcagca 480 ggatctgatc
aaccagggca acaagtggac tgtgaagatc ccgtcgagcc tcaggcccgg 540
aaactatgtc ttccgccatg aacttcttgc tgcccatggt gcctctagtg cgaacggcat
600 gcagaactat cctcagtgcg tgaacatcgc cgtcacaggc tcgggcacga
aagcgctccc 660 tgccggaact cctgcaactc agctttacaa gcccactgac
cctggcatct tgttcaaccc 720 ttacacaaca atcacgagct acaccatccc
tggcccagcc ctgtggcaag gctagatcca 780 ggggtacggt gttggcgttc
gtgaagtcgg agctgttgac aaggatatct gatgatgaac 840 ggagaggact
gatgggcgtg actgagtgta tatatttttg atgaccaaat tgtatacgaa 900
atccgaacgc atggtgatca ttgtttatcc ctgtagtata ttgtctccag gctgctaaga
960 gcccacgggt gtattacggc aacaaagtca ggaatttggg tggcaaaaaa
aaaaaaaaaa 1020 aaaaaaaaaa aaaaaaaaaa aaaaaaa 1047 2 230 PRT
Trichoderma reesei 2 His Gly Gln Val Gln Asn Phe Thr Ile Asn Gly
Gln Tyr Asn Gln Gly 1 5 10 15 Phe Ile Leu Asp Tyr Tyr Tyr Gln Lys
Gln Asn Thr Gly His Phe Pro 20 25 30 Asn Val Ala Gly Trp Tyr Ala
Glu Asp Leu Asp Leu Gly Phe Ile Ser 35 40 45 Pro Asp Gln Tyr Thr
Thr Pro Asp Ile Val Cys His Lys Asn Ala Ala 50 55 60 Pro Gly Ala
Ile Ser Ala Thr Ala Ala Ala Gly Ser Asn Ile Val Phe 65 70 75 80 Gln
Trp Gly Pro Gly Val Trp Pro His Pro Tyr Gly Pro Ile Val Thr 85 90
95 Tyr Val Val Glu Cys Ser Gly Ser Cys Thr Thr Val Asn Lys Asn Asn
100 105 110 Leu Arg Trp Val Lys Ile Gln Glu Ala Gly Ile Asn Tyr Asn
Thr Gln 115 120 125 Val Trp Ala Gln Gln Asp Leu Ile Asn Gln Gly Asn
Lys Trp Thr Val 130 135 140 Lys Ile Pro Ser Ser Leu Arg Pro Gly Asn
Tyr Val Phe Arg His Glu 145 150 155 160 Leu Leu Ala Ala His Gly Ala
Ser Ser Ala Asn Gly Met Gln Asn Tyr 165 170 175 Pro Gln Cys Val Asn
Ile Ala Val Thr Gly Ser Gly Thr Lys Ala Leu 180 185 190 Pro Ala Gly
Thr Pro Ala Thr Gln Leu Tyr Lys Pro Thr Asp Pro Gly 195 200 205 Ile
Leu Phe Asn Pro Tyr Thr Thr Ile Thr Ser Tyr Thr Ile Pro Gly 210 215
220 Pro Ala Leu Trp Gln Gly 225 230 3 19 PRT Trichoderma reesei 3
Met Lys Ser Cys Ala Ile Leu Ala Ala Leu Gly Cys Leu Ala Gly Ser 1 5
10 15 Val Leu Gly 4 750 DNA Trichoderma reesei 4 atgaagtcct
gcgccattct tgcagccctt ggctgtcttg ccgggagcgt tctcggccat 60
ggacaagtcc aaaacttcac gatcaatgga caatacaatc agggtttcat tctcgattac
120 tactatcaga agcagaatac tggtcacttc cccaacgttg ctggctggta
cgccgaggac 180 ctagacctgg gcttcatctc ccctgaccaa tacaccacgc
ccgacattgt ctgtcacaag 240 aacgcggccc caggtgccat ttctgccact
gcagcggccg gcagcaacat cgtcttccaa 300 tggggccctg gcgtctggcc
tcacccctac ggtcccatcg ttacctacgt ggttgagtgc 360 agcggatcgt
gcacgaccgt gaacaagaac aacctgcgct gggtcaagat tcaggaggcc 420
ggcatcaact ataacaccca agtctgggcg cagcaggatc tgatcaacca gggcaacaag
480 tggactgtga agatcccgtc gagcctcagg cccggaaact atgtcttccg
ccatgaactt 540 cttgctgccc atggtgcctc tagtgcgaac ggcatgcaga
actatcctca gtgcgtgaac 600 atcgccgtca caggctcggg cacgaaagcg
ctccctgccg gaactcctgc aactcagctt 660 tacaagccca ctgaccctgg
catcttgttc aacccttaca caacaatcac gagctacacc 720 atccctggcc
cagccctgtg gcaaggctag 750
* * * * *
References