Many microbial genes are subject to carbon catabolite repression (CCR), the repression in the presence of a preferred carbon source (e.g. glucose, sucrose) of the genes required for growth in the presence of less favourable carbon sources (e.g. acetamide, proline, quinate). In Aspergillus nidulans mutations which relieve CCR were previously selected as suppressors of the areA217 loss-of-function mutation for growth on sucrose plus acetamide. One class of recessive mutations map to creC, which is tightly linked to glnA on linkage group II. creC mutants display pleiotropic effects for growth on a range of carbon sources including decreased growth on some carbon sources such as quinate, and partially derepressed expression in repressing conditions of some enzymes such as alcohol dehydrogenase and acetamidase. We have exploited the proximity to glnA to clone by complementation the creC gene. Sequence analysis revealed that creC encodes a 630 amino acid polypeptide which contains a proline-rich region and WD40 repeats. CreC shows a high level of similarity with proteins of unknown function in Schizosaccharomyces pombe, mouse and human, but there is no close homologue in the Saccharomyces cerevisiae genome sequence. Regions of creC required for function have been localized by C-terminal deletion analysis and the determination of the sequence changes in creC mutant alleles.
Fungal Genet. Newsl. 46 (Supl):
Full conference title:
Fungal Genetics Conference 20th
- Fungal Genetics Conference 20th (1999)