In a previous study, a putative bZIP protein, RsmA (remediation of secondary metabolism A), was identified by using a multicopy-suppressor genetics approach in Aspergillus nidulans. Overexpression of rsmA partially restores sterigmatocystin (ST) production in Velvet Complex mutants via transcriptional induction of ST gene expression. RsmA has high sequence homology to the Yap family of proteins in Saccharomyces cerevisiae, specifically Yap3. In yeast, the Yap family of transcriptional regulators plays an important role in response to various environmental stressors. We conducted a microarray experiment that further validated that RsmA transcriptionally regulates the ST gene cluster as well as sexual development. Several key genes (e.g. sdeA, mpkB and trxA) involving in the sexual development were up- regulated or down-regulated. Moreover, secondary metabolite extractions from OE RsmA contain seven additional compounds that have similar UV-Vis spectra with the known compounds, indicating very strong induction of the ST cluster and other metabolites in OE RsmA strains. Physiological experiments indicated that sexual stage was greatly delayed in OE RsmA strain. Taken together, these data suggest that RsmA regulates both secondary metabolism and sexual development and propose that regulation by RsmA functions through transcriptional control of crucial genes. Overexpression and deletion of these genes are currently underway to confirm these results.
Full conference title:
26th Fungal Genetics Conference
- Fungal Genetics Conference 26th (2005)