Inducer Free Cellulase Secretion in Neurospora Crassa and comparitive analysis of cellulase induction in Aspergillus nidulans
Purpose: To explore conservation of gene regulation by the transcription factor clr-2/clrB in Neurospora crassa and Aspergillus nidulans Methods: mRNA from wild type and clr-2/clrB mutants were collected after a culture shift from sucrose/glucose to Avicel (crystaline cellulose) or no carbon media Results: We show that N. crassa and A. nidulans have similair global transcriptional responses to Avicel, with several hundred genes showing specific induction, though the induced genes are more specifically targeted at cellulose for N. crassa and more targeted at hemicellulose and pectin for A. nidulans.  clr-2/clrB has a conserved fundamental function in cellulose induction, though the mechanism has diverged.  Misexpression of clr-2 is sufficeint for inducer free cellulase secretion in N. crassa, but neither clrB or heterologous clr-2 is sufficient for inducer free cellulase secretion in A. nidulans. Conclusions: Our study demonstrates a conserved and essential role in cellulose utilization for the transcription factor clr-2 in filamentous ascomycetes and demonstrates that manipulation of clr-2 expression can be used to control cellulase expression in some species. Overall design: Biological triplicates of liquid culture N. crassa and A. nidulans were harvested at 4 hours and 6 hours, respectively, after a switch to media of interest.  Global mRNA abundances from liquid cultures of N. crassa and A. nidulans were measured by sequencing on the Illumina Genome Analyzer IIx and HiSeq2000 platforms.