A new Zn(II)(2)Cys(6)-type transcription factor BglR regulates β-glucosidase expression in Trichoderma reesei

Research output: Contribution to journalArticle

  • External authors:
  • Mikiko Nitta
  • Yosuke Shida
  • Kazuki Mori
  • Satoru Kuhara
  • Yasushi Morikawa
  • Wataru Ogasawara

Abstract

BglR (PI: 52368, beta-glucosidaseregulator) was identified as a new transcription factor that up-regulates expression of specific genes encoding β-glucosidases. Based on a comparative genomic analysis to verify SNPs between Trichoderma reesei mutant PC-3-7 and its parent KDG-12, 19 were confirmed. One of the SNPs was found to cause a missense mutation close to the end of the DNA-binding region of BglR that turned out to be a Zn(II)(2)Cys(6)-type fungal-specific transcription factor. BglR was found to share little homologous to amyR of Aspergillus oryzae that is commonly considered a key regulator of starch degradation. A mutant lacking the bglr gene as well as the PC-3-7 mutant exhibited elevated cellulase production during growth on cellobiose. Reversion of the SNP missence mutation within bglr to the wild-type allele resulted in reduced cellulase production. Expression of specific β-glucosidase genes in a bglr gene disruptant was repressed with the mutant exhibiting little ability to hydrolyze cellobiose during early log phase even when induced. Thus, one of the functions of BglR is to up-regulate specific β-glucosidase genes (with the exception of bgl1, which is seemingly under the direct control of Xyr1). The glucose produced then triggers carbon catabolite repression in cellobiose culture.

Bibliographical metadata

Original languageEnglish
Pages (from-to)388-397
Number of pages10
JournalFungal genetics and biology : FG & B
Volume49
Issue number5
DOIs
Publication statusPublished - May 2012