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Daniel Robyr

Publications and source records attributed to Daniel Robyr.

5 recordsLinked to original sources
PubMed2005

Genomewide analysis of nucleosome density histone acetylation and HDAC function in fission yeast.

We have conducted a genomewide investigation into the enzymatic specificity, expression profiles, and binding locations of four histone deacetylases (HDACs), representing the three different phylogenetic classes in fission yeast (Schizosaccharomyces pombe). By directly comparing nucleosome density, histone acetylation patterns and HDAC binding in both intergenic and coding regions with gene expression profiles, we found that Sir2 (class III) and Hos2 (class I) have a role in preventing histone loss; Clr6 (class I) is the principal enzyme in promoter-localized repression. Hos2 has an unexpected role in promoting high expression of growth-related genes by deacetylating H4K16Ac in their open reading frames. Clr3 (class II) acts cooperatively with Sir2 throughout the genome, including the silent regions: rDNA, centromeres, mat2/3 and telomeres. The most significant acetylation sites are H3K14Ac for Clr3 and H3K9Ac for Sir2 at their genomic targets. Clr3 also affects subtelomeric regions which contain clustered stress- and meiosis-induced genes. Thus, this combined genomic approach has uncovered different roles for fission yeast HDACs at the silent regions in repression and activation of gene expression.

Acetylation↗
PubMed2003

Genomewide histone acetylation microarrays.

Histone acetylation and methylation are important regulators of gene activity. Chromatin immunoprecipitation (ChIP or ChrIP) has made it possible to examine not only the state of histone acetylation at a gene but also that of histone methylation and may soon be extended to other histone modifications such as phosphorylation and ubiquitination. In principle such studies are possible as long as an antibody is available to the particular histone modification. Once a target gene is identified it is instructive to see the effect of mutating putative enzymes responsible for the modification to determine how a particular enzyme is responsible for altering chromatin of that gene. Although specific target genes have been studied that contain such modifications recent technical advances have made it possible to study histone modifications genomewide. This not only allows for alternate views of particular paradigms to be investigated, but also uncovers chromosomal patterns of histone modification that would be missed in analyzing individual genes. We describe here an approach to rapidly study histone modifications genomewide by combining chromatin immunoprecipitation and DNA microarrays.

Acetylation↗
PubMed2002

Genome-wide binding map of the histone deacetylase Rpd3 in yeast.

We describe the genome-wide distribution of the histone deacetylase and repressor Rpd3 and its associated proteins Ume1 and Ume6 in Saccharomyces cerevisiae. Using a new cross-linking protocol, we found that Rpd3 binds upstream of many individual genes and upstream of members of gene classes with similar functions in anabolic processes. In addition, Rpd3 is preferentially associated with promoters that direct high transcriptional activity. We also found that Rpd3 was absent from large sub-telomeric domains. We show by co-immunoprecipitation and by the high similarity of their binding maps that Ume1 interacts with Rpd3. In contrast, despite the known role of Ume6 in Rpd3 recruitment, only a limited number of the genes targeted by Rpd3 are also enriched for (or targeted by) Ume6. This suggests that Rpd3 is brought to many promoters by alternative recruiters, some of which may bind the putative cis-regulatory DNA elements that we have identified in sets of Rpd3 target genes. Finally, we show that comparing the genome-wide pattern of Rpd3 binding with gene expression and histone acetylation in the rpd3 Delta mutant strain reveals new sites of Rpd3 function.

Acetylation↗
PubMed2002

Microarray deacetylation maps determine genome-wide functions for yeast histone deacetylases.

Yeast contains a family of five related histone deacetylases (HDACs) whose functions are known at few genes. Therefore, we used chromatin immunoprecipitation and intergenic microarrays to generate genome-wide HDAC enzyme activity maps. Rpd3 and Hda1 deacetylate mainly distinct promoters and gene classes where they are recruited largely by novel mechanisms. Hda1 also deacetylates subtelomeric domains containing normally repressed genes that are used instead for gluconeogenesis, growth on carbon sources other than glucose, and adverse growth conditions. These domains have certain features of heterochromatin but are distinct from subtelomeric heterochromatin repressed by the deacetylase Sir2. Finally, Hos1/Hos3 and Hos2 preferentially affect ribosomal DNA and ribosomal protein genes, respectively. Thus, acetylation microarrays uncover the "division of labor" for yeast histone deacetylases.

Carrier Proteins↗