title: Differential recruitment of glucocorticoid receptor phospho-isoforms to glucocorticoid-induced genes.
abstract: The human glucocorticoid receptor (GR) is phosphorylated on its N-terminus at three major sites (S203, S211 and S226) within activation function 1 (AF1). Although GR has been shown to assemble at glucocorticoid responsive elements (GREs) in the presence of hormone, the timing and specificity of GR phospho-isoform recruitment to receptor target genes has not been established. Using chromatin immunoprecipitation (ChIP) and GR phosphorylation site-specific antibodies, we examined GR phospho-isoform recruitment to several glucocorticoid-induced genes including tyrosine aminotransferase (tat) and sulfonyltransferase-1A1 (sult) in rat hepatoma cells, and the glucocorticoid-induced leucine zipper (gilz) gene in human U2OS cells. GR P-S211 and GR P-S226 isoforms were efficiently recruited to the tat, sult and gilz GREs in a hormone-dependent manner. In contrast, the GR P-S203 isoform displayed no significant recruitment to any GREs of the genes analyzed, consistent with its lack of nuclear accumulation. Interestingly, the kinetics of GR P-S211 and GR P-S226 recruitment differed among genes. Our findings indicate that GR phospho-isoforms selectively occupy GR target genes, and suggests gene specific requirements for GR phosphorylation in receptor-dependent transcriptional activation.
authors.affiliation: Department of Microbiology, NYU Cancer Institute, NYU School of Medicine, 550 First Avenue, New York, NY 10016, United States.
authors.forename: Raymond D
authors.initials: RD
authors.lastname: Blind
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Garabedian
mesh_terms: D000818:Animals; D015239:Arylsulfotransferase / Q000235:genetics; D001483:Base Sequence; D001665:Binding Sites / Q000235:genetics; D045744:Cell Line, Tumor; D004247:DNA / Q000235:genetics / Q000378:metabolism; D017931:DNA Primers / Q000235:genetics; D003907:Dexamethasone / Q000494:pharmacology*; D006801:Humans; D010766:Phosphorylation; D020033:Protein Isoforms / Q000737:chemistry / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D051381:Rats; D011965:Receptors, Glucocorticoid / Q000737:chemistry / Q000378:metabolism*; D014157:Transcription Factors / Q000235:genetics; D015533:Transcriptional Activation / Q000187:drug effects*; D014444:Tyrosine Transaminase / Q000235:genetics
chemical_list: D017931:DNA Primers; D020033:Protein Isoforms; D012333:RNA, Messenger; D011965:Receptors, Glucocorticoid; C404226:TSC22D3 protein, human; D014157:Transcription Factors; D003907:Dexamethasone; D004247:DNA; D014444:Tyrosine Transaminase; D015239:Arylsulfotransferase