Roles of the Aspergillus nidulans homologues of Tup1 and Ssn6 in chromatin structure and cell viability

Abstract

For three different carbon catabolite repressible promoters, alcA, alcR and the bidirectional promoter prnD-prnB, a deletion of rcoA, the Aspergillus nidulans homologue of TUP1, does not result in carbon catabolite derepression. Surprisingly, it results in disruption of the chromatin default structure of alcR and prnD-prnB promoters. In these promoters, and at variance with the wild type, repression occurs in the absence of nucleosome positioning. For alcR, repression occurs together with a nucleosome pattern identical to that found under conditions of full expression, and for prnD-prnB it occurs with a novel pattern that does not correspond to the pattern seen under conditions of repression in a wild-type strain. Deletion of the putative RcoA partner, SsnF, is lethal in A. nidulans. © 2008 Federation of European Microbiological Societies. Published by Blackwell Publishing Ltd. All rights reserved.