Deletion of the middle region of the transcription factor ClrB in Penicillium oxalicum enables cellulase production in the presence of glucose [Gene Regulation]

In this study, using a reporter gene system in yeast, we identified the C-terminal region of ClrB/CLR-2 as a transcriptional activation domain. Expression of clrBID, encoding a ClrB derivative in which the DNA-binding and transcriptional activation domains are fused together to remove the middle region, led to cellulase production in the absence of cellulose in P. oxalicum. Strikingly, the clrBID-expressing strain produced cellulase on carbon sources that normally repress cellulase expression, including glucose and glycerol. Results from deletion of the carbon catabolite repressor gene creA in the clrBID-expressing strain suggested that the effect of clrBID is independent of CreA's repressive function. A similar modification of clrB in Aspergillus niger resulted in the production of a mannanase in glucose medium. Taken together, these results indicate that ClrB suppression under noninducing conditions involves its middle region, suggesting a potential strategy to engineer fungal strains for improved cellulase production on commonly used carbon sources.

Source: Journal of Biological Chemistry - December 5, 2019 Category: Chemistry Authors: Liwei Gao, Yanning Xu, Xin Song, Shiying Li, Chengqiang Xia, Jiadi Xu, Yuqi Qin, Guodong Liu, Yinbo Qu Tags: Microbiology Source Type: research