Involvement of an SRF-MADS protein McmA in regulation of extracellular enzyme production and asexual/sexual development in Aspergillus nidulans.

SRF-MADS proteins are transcription factors conserved among eukaryotes that regulate a variety of cellular functions; however, their physiological roles are still not well understood in filamentous fungi. Effects of a mutation in mcmA gene that encodes the sole SRF-MADS protein in the fungus Aspergillus nidulans were examined by RNA sequencing. Sequencing data revealed that expression levels of cellulase genes were significantly decreased by the mutation as reported previously.

Regulation of cellulolytic genes by McmA, the SRF-MADS box protein in Aspergillus nidulans.

Cellobiose triggers the production of two endoglucanases, EglA and EglB, in Aspergillus nidulans. The cellulose responsive element (CeRE) cis-element that is essential for induction has been identified on the eglA promoter, but transcription factors that bind to CeRE have not yet been identified. CeRE contained a consensus sequence CC(A/T)6GG for binding of the SRF-type MADS box proteins.

Novel promoter sequence required for inductive expression of the Aspergillus nidulans endoglucanase gene eglA.

Expression of the eglA gene, encoding for a major endoglucanse EG A in Aspergillus nidulans, is induced by cellulose and cellobiose, but not by xylose. This suggests that induction is independent of XlnR, a transcriptional activator of xylanolytic and cellulolytic genes in Aspergillus. Mutational analysis of the eglA promoter was performed to identify the novel cis-element responsible for XlnR-independent induction.