title: High throughput screening identifies modulators of histone deacetylase inhibitors.
abstract: BACKGROUND
  Previous studies from our laboratory and others have demonstrated that in addition to altering chromatin acetylation and conformation, histone deacetylase inhibitors (HDACi) disrupt the acetylation status of numerous transcription factors and other proteins. A whole genome yeast deletion library screen was used to identify components of the transcriptional apparatus that modulate the sensitivity to the hydroxamic acid-based HDACi, CG-1521.
  
  
  RESULTS
  Screening 4852 haploid Saccharomyces cerevisiae deletion strains for sensitivity to CG-1521 identifies 407 sensitive and 80 resistant strains. Gene ontology (GO) enrichment analysis shows that strains sensitive to CG-1521 are highly enriched in processes regulating chromatin remodeling and transcription as well as other ontologies, including vacuolar acidification and vesicle-mediated transport. CG-1521-resistant strains include those deficient in the regulation of transcription and tRNA modification. Components of the SAGA histone acetyltransferase (HAT) complex are overrepresented in the sensitive strains, including the catalytic subunit, Gcn5. Cell cycle analysis indicates that both the wild-type and gcn5Δ strains show a G1 delay after CG-1521 treatment, however the gcn5Δ strain displays increased sensitivity to CG-1521-induced cell death compared to the wild-type strain. To test whether the enzymatic activity of Gcn5 is necessary in the response to CG-1521, growth assays with a yeast strain expressing a catalytically inactive variant of the Gcn5 protein were performed and the results show that this strain is less sensitive to CG-1521 than the gcn5Δ strain.
  
  
  CONCLUSIONS
  Genome-wide deletion mutant screening identifies biological processes that affect the sensitivity to the HDAC inhibitor CG-1521, including transcription and chromatin remodeling. This study illuminates the pathways involved in the response to CG-1521 in yeast and provides incentives to understand the mechanisms of HDAC inhibitors in cancer cells. The data presented here demonstrate that components of the SAGA complex are involved in mediating the response to CG-1521. Additional experiments suggest that functions other than the acetyltransferase activity of Gcn5 may be sufficient to attenuate the effects of CG-1521 on cell growth.
authors: Ann-Christin
authors: AC
authors: Gaupel
authors: Thomas
authors: T
authors: Begley
authors: Department of Biomedical Sciences, School of Public Health, University at Albany, New York 12222, USA. mtenniswood@albany.edu.
authors: Martin
authors: M
authors: Tenniswood
mesh_terms: D002453:Cell Cycle / Q000187:drug effects / Q000235:genetics; D016923:Cell Death / Q000187:drug effects / Q000235:genetics; D042002:Chromatin Assembly and Disassembly / Q000187:drug effects / Q000235:genetics; D019295:Computational Biology; D055808:Drug Discovery; D025141:Drug Resistance, Fungal / Q000235:genetics; D005838:Genotype; D057166:High-Throughput Screening Assays; D051548:Histone Acetyltransferases / Q000235:genetics / Q000378:metabolism; D056572:Histone Deacetylase Inhibitors / Q000494:pharmacology*; D006655:Histone Deacetylases; D006877:Hydroxamic Acids / Q000494:pharmacology; D008826:Microbial Sensitivity Tests; D009154:Mutation; D010641:Phenotype; D012441:Saccharomyces cerevisiae / Q000187:drug effects / Q000235:genetics / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism; D014158:Transcription, Genetic / Q000187:drug effects
chemical_list: C531199:7-phenyl-2,4,6-heptatrienoylhydroxamic acid; D056572:Histone Deacetylase Inhibitors; D006877:Hydroxamic Acids; D029701:Saccharomyces cerevisiae Proteins; D051548:Histone Acetyltransferases; D006655:Histone Deacetylases