Characterization of two putative histone deacetylase genes from Aspergillus nidulans

In eukaryotic organisms, acetylation of core histones plays a key role in t he regulation of transcription. Multiple histone acetyltransferases (HATs) and histone deacetylases (HDACs) maintain a dynamic equilibrium of histone acetylation. The latter form a highly conserved protein family in many euka ryotic species. In this paper, we report the cloning and sequencing of two putative histone deacetylase genes (rpdA, hosA) of Aspergillus nidulans, wh ich are the first to be analyzed from filamentous fungi. Hybridization with a chromosome-specific cosmid library of A. nidulans allowed the localizati on of rpdA to chromosome III and hosA to chromosome II, respectively. PCR a nalyses and Southern hybridization experiments revealed that no further mem bers of the RPD3 family are present in the genome of the fungus. Although s equence alignment displays significant amino acid similarity to other eukar yotic RPD3-type deacetylases, the deduced RPDA sequence reveals an unusual 200-amino acid extension at the C-terminus. Expression of both. genes was d etermined by RNA blot analysis. Treatment of the cells with trichostatin A (TSA), a potent inhibitor of HDACs, was found to stimulate expression of rp dA of A. nidulans. (C) 2000 Elsevier Science B.V. All rights reserved.