title: Combinatorial Screening for Transgenic Yeasts with High Cellulase Activities in Combination with a Tunable Expression System.
abstract: Combinatorial screening used together with a broad library of gene expression cassettes is expected to produce a powerful tool for the optimization of the simultaneous expression of multiple enzymes. Recently, we proposed a highly tunable protein expression system that utilized multiple genome-integrated target genes to fine-tune enzyme expression in yeast cells. This tunable system included a library of expression cassettes each composed of three gene-expression control elements that in different combinations produced a wide range of protein expression levels. In this study, four gene expression cassettes with graded protein expression levels were applied to the expression of three cellulases: cellobiohydrolase 1, cellobiohydrolase 2, and endoglucanase 2. After combinatorial screening for transgenic yeasts simultaneously secreting these three cellulases, we obtained strains with higher cellulase expressions than a strain harboring three cellulase-expression constructs within one high-performance gene expression cassette. These results show that our method will be of broad use throughout the field of metabolic engineering.
authors.affiliation: Matsuyama Research Group, TOYOTA Central Research and Development Laboratories Incorporation, Nagakute, Aichi, Japan.
authors.forename: Yoichiro
authors.initials: Y
authors.lastname: Ito
authors.affiliation: Matsuyama Research Group, TOYOTA Central Research and Development Laboratories Incorporation, Nagakute, Aichi, Japan.
authors.forename: Mamoru
authors.initials: M
authors.lastname: Yamanishi
authors.affiliation: Biotechnology Laboratory, TOYOTA Central Research and Development Laboratories Incorporation, Nagakute, Aichi, Japan.
authors.forename: Akinori
authors.initials: A
authors.lastname: Ikeuchi
authors.affiliation: Biotechnology Laboratory, TOYOTA Central Research and Development Laboratories Incorporation, Nagakute, Aichi, Japan.
authors.forename: Chie
authors.initials: C
authors.lastname: Imamura
authors.affiliation: Matsuyama Research Group, TOYOTA Central Research and Development Laboratories Incorporation, Nagakute, Aichi, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Matsuyama
mesh_terms: D002480:Cellulase / Q000096:biosynthesis* / Q000235:genetics; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism*; D005656:Fungal Proteins / Q000096:biosynthesis* / Q000235:genetics; D015870:Gene Expression; D020075:Phanerochaete / Q000201:enzymology / Q000235:genetics*; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000235:genetics; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism*; D032901:Talaromyces / Q000201:enzymology / Q000235:genetics*
chemical_list: D005656:Fungal Proteins; D011994:Recombinant Proteins; D002480:Cellulase