Growth and development of prokaryotic and eukaryotic cells depends on a coordinated gene expression. Thereby regulation on the level of transcription plays an essential role in all organisms. In eukaryotes, transcriptionally active genes are preferentially localized in genomic regions enriched in acetylated histones. The dynamic equilibrium of core histone acetylation is maintained by histone acetyl-transfeiases and deacetylases. Both enzymes often function as components of regulator complexes targeted to particular genes by DNA binding transcription factors. Using PCR approaches, we have cloned and sequenced cDNA fragments of arpd3 and ahos2, two putative histone deacetylases from Aspergillus nidulans, which are the first deacetylases to be analyzed from a filamentous fungus. Comparisons of the cloned sequences with the GenBank database revealed high similarity to RPD3-type deacetylases from Saccharomyces cerevisiae. Hybridization of these cDNA fragments with a chromosome-specific cosmid library of A. nidulans allowed the chromosomal localization of both genes and led to the genomic sequence of arpd3. Moreover, comparison between this sequence and the corresponding cDNA revealed 3 introns interrupting an open reading frame of 2028 bp, which encodes a protein of 676 amino acids with a predicted molecular weight of 75 kDa. Compared to different yeast RPD3-type deacetylases the deduced ARPD3 amino acid sequence reveales a considerable extension of the C-terminus. Currently, we are using northern hybridization analysis in order to determine the expression levels of ARPD3 and AHOS2 in different developmental states and distinct growth conditions of the fungus.
Fungal Genet. Newsl. 46 (Supl):
Full conference title:
Fungal Genetics Conference 20th
- Fungal Genetics Conference 20th (1999)