title: Detection of an altered heterochromatin structure in the absence of the nucleotide excision repair protein Rad4 in Saccharomyces cerevisiae.
abstract: Rad4p is a DNA damage recognition protein essential for global genomic nucleotide excision repair in Saccharomyces cerevisiae. Here, we show that Rad4p binds to the heterochromatic HML locus. In a yeast mutant lacking Rad4p, an increased level of SIR complex binding at the HML locus is accompanied by an altered, more compact heterochromatin structure, as revealed by a topological analysis of chromatin circles released from the locus. In addition, gene silencing at the HML locus is enhanced in the rad4Δ mutant. Importantly, re-expression of Rad4p in the rad4Δ mutant restores the altered heterochromatin structure to a conformation similar to that detected in wild-type cells. These findings reveal a novel role of Rad4p in the regulation of heterochromatin structure and gene silencing.
authors.affiliation: Department of Biochemistry and Molecular Biology; University of Miami Miller School of Medicine; Miami, FL USA.
authors.forename: Ling
authors.initials: L
authors.lastname: Zhang
authors.forename: Hua
authors.initials: H
authors.lastname: Chen
authors.forename: Xin
authors.initials: X
authors.lastname: Bi
authors.forename: Feng
authors.initials: F
authors.lastname: Gong
mesh_terms: D004260:DNA Repair; D004268:DNA-Binding Proteins / Q000172:deficiency / Q000235:genetics*; D015870:Gene Expression; D015966:Gene Expression Regulation, Fungal; D055786:Gene Knockout Techniques; D020868:Gene Silencing; D005800:Genes, Fungal; D056426:Genetic Loci; D006570:Heterochromatin / Q000235:genetics / Q000378:metabolism*; D011485:Protein Binding; D012441:Saccharomyces cerevisiae / Q000235:genetics* / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics*; D038281:Silent Information Regulator Proteins, Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism
chemical_list: D004268:DNA-Binding Proteins; D006570:Heterochromatin; C493797:Rad4 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D038281:Silent Information Regulator Proteins, Saccharomyces cerevisiae; C554167:URA3 protein, S cerevisiae
keywords: HML; Rad4p; SIR complex; heterochromatin; nucleotide excision repair