title: Histone H1 and H3 dephosphorylation are differentially regulated by radiation-induced signal transduction pathways.
abstract: We recently demonstrated that linker histone H1, which is thought to have a fundamental role in higher-order chromatin structure, becomes transiently dephosphorylated after ionizing radiation (IR) in a mutated ataxia telangiectasia (ATM) dependent manner. To establish whether H1 dephosphorylation was a component of a damage-response pathway that included dephosphorylation of other histones, we asked whether H3 was dephosphorylated in response to IR in a manner similar to H1. H1 and H3 are maximally phosphorylated in metaphase and both are dephosphorylated after IR. However, the duration of IR-induced H3 dephosphorylation is significantly longer than that of IR-induced H1 dephosphorylation. Moreover, H1 dephosphorylation is ATM-dependent, whereas H3 dephosphorylation is ATM-independent. These observations suggest that the damage-sensing pathways regulating H3 and H1 dephosphorylation diverge upstream of ATM.
authors.affiliation: Department of Radiation Oncology, University of Virginia Health Science System, Charlottesville 22908, USA.
authors.forename: C Y
authors.initials: CY
authors.lastname: Guo
authors.forename: C
authors.initials: C
authors.lastname: Mizzen
authors.forename: Y
authors.initials: Y
authors.lastname: Wang
authors.forename: J M
authors.initials: JM
authors.lastname: Larner
mesh_terms: D000818:Animals; D001260:Ataxia Telangiectasia / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D016466:CHO Cells / Q000166:cytology / Q000378:metabolism / Q000528:radiation effects; D002460:Cell Line; D006224:Cricetinae; D050759:Cyclin-Dependent Kinase Inhibitor p21; D016213:Cyclins / Q000502:physiology; D005347:Fibroblasts / Q000378:metabolism / Q000528:radiation effects; D016195:G2 Phase / Q000502:physiology / Q000528:radiation effects; D006657:Histones / Q000378:metabolism* / Q000528:radiation effects; D006801:Humans; D019169:Jurkat Cells / Q000166:cytology / Q000378:metabolism / Q000528:radiation effects; D007700:Kinetics; D008938:Mitosis / Q000502:physiology / Q000528:radiation effects; D010766:Phosphorylation / Q000528:radiation effects; D015398:Signal Transduction / Q000528:radiation effects*; D016159:Tumor Suppressor Protein p53 / Q000502:physiology
chemical_list: C493956:CDKN1A protein, human; D050759:Cyclin-Dependent Kinase Inhibitor p21; D016213:Cyclins; D006657:Histones; D016159:Tumor Suppressor Protein p53