Elucidation of signal transduction network related to repression of genes for polysaccharide degrading enzymes in filamentous fungi

2020 Fiscal Year Final Research Report

• Project/Area Number: 18H02125
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Review Section: Basic Section 38020:Applied microbiology-related
• Research Institution: Nagoya University
• Principal Investigator: Kobayashi Tetsuo 名古屋大学, 生命農学研究科, 教授 (20170334)
• Co-Investigator(Kenkyū-buntansha): 國武 絵美 三重大学, 生物資源学研究科, 助教 (30800586)
• Project Period (FY): 2018-04-01 – 2021-03-31
• Keywords: カーボンカタボライト抑制 / Aspergillus nidulans / 多糖分解酵素 / 転写制御

Outline of Final Research Achievements

Production of polysaccharide degrading enzymes in filamentous fungi is generally under regulation of carbon catabolite repression (CCR), however, sensitivity to CCR differs depending on the enzyme type. Strength of CCR also differs depending on the repressing carbon source. Thus, the production is finely regulated. CCR is mediated by the transcription factor CreA as well as by PkaA and GanB in Aspergillus nidulans. The deubiquitinase CreB is also required for CCR. To further understand mechanisms of CCR, we compared the effects of creA deletion with deletion of pkaA and ganB genes as well as creB. This study revealed that PkaA and GanB participate in CreA-independent CCR and that contribution of CreA, PkaA, and GanB in CCR differs depending on the inducers, repressing carbon sources, the enzyme types and culture conditions. It also revealed that CreB functions independently of GanB. In addition, we identified a promising candidate of PkaA substrate that regulates CCR.

Free Research Field

応用微生物学

Academic Significance and Societal Importance of the Research Achievements

糸状菌由来の多糖分解酵素は市場性の高い有用酵素であり、食品、繊維などの産業で幅広く利用されている。さらに、バイオマス有効利用の観点から近年需要が高まっている。そこで酵素価格を低く抑える必要があるが、そのネックとなる原因の一つがカーボンカタボライト抑制による生産量の低下である。本研究では複数の独立した経路がCCRに関わることを示し、多重破壊株を用いた効率的酵素生産法確率のための基盤情報を提供した。