title: Simultaneous expression of the bacterial Dictyoglomus thermophilum xynB gene under three different Trichoderma reesei promoters.
abstract: Multiple copies of expression cassettes driven by the Trichoderma reesei xylanase 2 (xyn2) and cellobiohydrolase 2 (cbh2) promoters were introduced into the recombinant T. reesei EC-21 generated to express a thermostable Dictyoglomus thermophilum xylanase (XynB) under the egl2 promoter for further improvement of the enzyme yield. The transformants were screened based on increased XynB activity only. Multiple promoter transformant MPP-4 expressing the xynB gene under all the three promoters was found to be the highest producer of XynB, giving a 65% increase in yield compared to the parental single-promoter recombinant EC-21. The multiple-promoter transformant strains harboured six to nine copies of the xynB gene. Amongst the three promoters, egl2 seemed to have the strongest effect on XynB expression. The shotgun approach we used proved to be effective for rapid enhancement of protein expression using three promoters active at the near-neutral pH of the cultivation medium.
authors.affiliation: Department of Chemistry and Biomolecular Sciences, Macquarie University, North Ryde, NSW 2109, Australia; Biomolecular Frontiers Research Centre, Macquarie University, North Ryde, NSW 2109, Australia.
authors.forename: Shingo
authors.initials: S
authors.lastname: Miyauchi
authors.forename: V S Junior
authors.initials: VS
authors.lastname: Te'o
authors.forename: K M Helena
authors.initials: KM
authors.lastname: Nevalainen
authors.forename: Peter L
authors.initials: PL
authors.lastname: Bergquist
mesh_terms: D001419:Bacteria / Q000201:enzymology / Q000235:genetics*; D001426:Bacterial Proteins / Q000096:biosynthesis* / Q000235:genetics; D043364:Endo-1,4-beta Xylanases / Q000096:biosynthesis* / Q000235:genetics; D015870:Gene Expression; D011401:Promoter Regions, Genetic; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000235:genetics; D014242:Trichoderma / Q000235:genetics / Q000378:metabolism*; D001617:beta-Glucosidase / Q000096:biosynthesis* / Q000235:genetics
chemical_list: D001426:Bacterial Proteins; D011994:Recombinant Proteins; D001617:beta-Glucosidase; D043364:Endo-1,4-beta Xylanases; C090001:XynB xylanase