title: Gene reactivation by 5-aza-2'-deoxycytidine-induced demethylation requires SRCAP-mediated H2A.Z insertion to establish nucleosome depleted regions.
abstract: 5-Aza-2'-deoxycytidine, approved by the FDA for the treatment of myelodysplastic syndrome (MDS), is incorporated into the DNA of dividing cells where it specifically inhibits DNA methylation by forming covalent complexes with the DNA methyltransferases (DNMTs). In an effort to study the correlations between DNA methylation, nucleosome remodeling, and gene reactivation, we investigate the integrated epigenetic events that worked coordinately to reprogram the methylated and closed promoters back to permissive chromatin configurations after 5-Aza-2'-deoxycytidine treatment. The ChIP results indicate that H2A.Z is deposited at promoter regions by the Snf2-related CBP activator protein (SRCAP) complex following DNA demethylation. According to our genome-wide expression and DNA methylation profiles, we find that the complete re-activation of silenced genes requires the insertion of the histone variant H2A.Z, which facilitates the acquisition of regions fully depleted of nucleosome as demonstrated by NOMe-seq (Nucleosome Occupancy Methylome-sequencing) assay. In contrast, SRCAP-mediated H2A.Z deposition is not required for maintaining the active status of constitutively expressed genes. By combining Hpa II digestion with NOMe-seq assay, we show that hemimethylated DNA, which is generated following drug incorporation, remains occupied by nucleosomes. Our data highlight H2A.Z as a novel and essential factor involved in 5-Aza-2'-deoxycytidine-induced gene reactivation. Furthermore, we elucidate that chromatin remodeling translates the demethylation ability of DNMT inhibitors to their downstream efficacies, suggesting future therapeutic implications for chromatin remodelers.
authors.affiliation: Department of Urology, Norris Comprehensive Cancer Center, Keck School of Medicine, University of Southern California, Los Angeles, California, United States of America.
authors.forename: Xiaojing
authors.initials: X
authors.lastname: Yang
authors.forename: Houtan
authors.initials: H
authors.lastname: Noushmehr
authors.forename: Han
authors.initials: H
authors.lastname: Han
authors.forename: Claudia
authors.initials: C
authors.lastname: Andreu-Vieyra
authors.forename: Gangning
authors.initials: G
authors.lastname: Liang
authors.forename: Peter A
authors.initials: PA
authors.lastname: Jones
mesh_terms: D000251:Adenosine Triphosphatases / Q000235:genetics / Q000378:metabolism; D001374:Azacitidine / Q000031:analogs & derivatives* / Q000494:pharmacology; D045744:Cell Line, Tumor; D042002:Chromatin Assembly and Disassembly / Q000235:genetics*; D019175:DNA Methylation / Q000187:drug effects / Q000235:genetics; D015254:DNA Modification Methylases / Q000037:antagonists & inhibitors / Q000378:metabolism; D000077209:Decitabine; D044127:Epigenesis, Genetic; D005786:Gene Expression Regulation / Q000187:drug effects; D055785:Gene Knockdown Techniques; D006657:Histones / Q000235:genetics / Q000378:metabolism; D006801:Humans; D009707:Nucleosomes / Q000235:genetics; D011401:Promoter Regions, Genetic; D015533:Transcriptional Activation / Q000187:drug effects / Q000235:genetics
chemical_list: D006657:Histones; D009707:Nucleosomes; C077020:histone H2A.F-Z; D000077209:Decitabine; D015254:DNA Modification Methylases; D000251:Adenosine Triphosphatases; C119652:SRCAP protein, human; D001374:Azacitidine