Redesigning transcription factor Cre1 for alleviating carbon catabolite repression in Trichoderma reesei

Lijuan Han; Kuimei Liu; Wei Ma; Yi Jiang; Shaoli Hou; Yinshuang Tan; Quanquan Yuan; Kangle Niu; Xu Fang

doi:10.1016/j.synbio.2020.07.002

Redesigning transcription factor Cre1 for alleviating carbon catabolite repression in Trichoderma reesei

Synth Syst Biotechnol. 2020 Jul 15;5(3):230-235. doi: 10.1016/j.synbio.2020.07.002. eCollection 2020 Sep.

Authors

Lijuan Han¹, Kuimei Liu^{1

2}, Wei Ma¹, Yi Jiang¹, Shaoli Hou³, Yinshuang Tan¹, Quanquan Yuan¹, Kangle Niu¹, Xu Fang^{1

3}

Affiliations

¹ State Key Laboratory of Microbial Technology, Shandong University, Qingdao, 266237, China.
² Rongcheng Campus, Harbin University of Science and Technology, Weihai, 264300, China.
³ Shandong Henglu Biological Technology Co., Ltd, Jinan, 250000, China.

Abstract

Carbon catabolite repression (CCR), which is mainly mediated by Cre1 and triggered by glucose, leads to a decrease in cellulase production in Trichoderma reesei. Many studies have focused on modifying Cre1 for alleviating CCR. Based on the homologous alignment of CreA from wild-type Penicillium oxalicum 114-2 (Po-0) and cellulase hyperproducer JUA10-1(Po-1), we constructed a C-terminus substitution strain-Po-2-with decreased transcriptional levels of cellulase and enhanced CCR. Results revealed that the C-terminal domain of CreA^Po-1 plays an important role in alleviating CCR. Furthermore, we replaced the C-terminus of Cre1 with that of CreA^Po-1 in T. reesei (Tr-0) and generated Tr-1. As a control, the C-terminus of Cre1 was truncated and Tr-2 was generated. The transcriptional profiles of these transformants revealed that the C-terminal chimera greatly improves cellulase transcription in the presence of glucose and thus upregulates cellulase in the presence of glucose and weakens CCR, consistent with truncating the C-terminus of Cre1 in Tr-0. Therefore, we propose constructing a C-terminal chimera as a new strategy to improve cellulase production and alleviate CCR in the presence of glucose.

Keywords: Carbon catabolite repression; Chimera; Cre1; Trichoderma reesei; cel7a.