title: Identification of the CRE-1 cellulolytic regulon in Neurospora crassa.
abstract: BACKGROUND
  In filamentous ascomycete fungi, the utilization of alternate carbon sources is influenced by the zinc finger transcription factor CreA/CRE-1, which encodes a carbon catabolite repressor protein homologous to Mig1 from Saccharomyces cerevisiae. In Neurospora crassa, deletion of cre-1 results in increased secretion of amylase and β-galactosidase.
  
  
  RESULTS
  Here we show that a strain carrying a deletion of cre-1 has increased cellulolytic activity and increased expression of cellulolytic genes during growth on crystalline cellulose (Avicel). Constitutive expression of cre-1 complements the phenotype of a N. crassa Δcre-1 strain grown on Avicel, and also results in stronger repression of cellulolytic protein secretion and enzyme activity. We determined the CRE-1 regulon by investigating the secretome and transcriptome of a Δcre-1 strain as compared to wild type when grown on Avicel versus minimal medium. Chromatin immunoprecipitation-PCR of putative target genes showed that CRE-1 binds to only some adjacent 5'-SYGGRG-3' motifs, consistent with previous findings in other fungi, and suggests that unidentified additional regulatory factors affect CRE-1 binding to promoter regions. Characterization of 30 mutants containing deletions in genes whose expression level increased in a Δcre-1 strain under cellulolytic conditions identified novel genes that affect cellulase activity and protein secretion.
  
  
  CONCLUSIONS
  Our data provide comprehensive information on the CRE-1 regulon in N. crassa and contribute to deciphering the global role of carbon catabolite repression in filamentous ascomycete fungi during plant cell wall deconstruction.
authors: Department of Plant and Microbial Biology, University of California, Berkeley, California, United States of America.
authors: Jianping
authors: J
authors: Sun
authors: N Louise
authors: NL
authors: Glass
mesh_terms: D020816:Amino Acid Motifs; D002480:Cellulase / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism; D002482:Cellulose / Q000378:metabolism*; D047369:Chromatin Immunoprecipitation; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism*; D017353:Gene Deletion; D015966:Gene Expression Regulation, Fungal / Q000235:genetics; D009154:Mutation; D009492:Neurospora crassa / Q000201:enzymology / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism*; D018085:Regulon / Q000235:genetics*; D012097:Repressor Proteins / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*
chemical_list: D005656:Fungal Proteins; D012097:Repressor Proteins; D002482:Cellulose; D002480:Cellulase