title: Increased ionizing radiation sensitivity and genomic instability in the absence of histone H2AX.
abstract: In mammalian cells, DNA double-strand breaks (DSBs) cause rapid phosphorylation of the H2AX core histone variant (to form gamma-H2AX) in megabase chromatin domains flanking sites of DNA damage. To investigate the role of H2AX in mammalian cells, we generated H2AX-deficient (H2AX(Delta)/Delta) mouse embryonic stem (ES) cells. H2AX(Delta)/Delta ES cells are viable. However, they are highly sensitive to ionizing radiation (IR) and exhibit elevated levels of spontaneous and IR-induced genomic instability. Notably, H2AX is not required for NHEJ per se because H2AX(Delta)/Delta ES cells support normal levels and fidelity of V(D)J recombination in transient assays and also support lymphocyte development in vivo. However, H2AX(Delta)/Delta ES cells exhibit altered IR-induced BRCA1 focus formation. Our findings indicate that H2AX function is essential for mammalian DNA repair and genomic stability.
authors.affiliation: Howard Hughes Medical Institute, Department of Genetics, Children's Hospital, Boston, MA 02115, USA.
authors.forename: Craig H
authors.initials: CH
authors.lastname: Bassing
authors.forename: Katrin F
authors.initials: KF
authors.lastname: Chua
authors.forename: JoAnn
authors.initials: J
authors.lastname: Sekiguchi
authors.forename: Heikyung
authors.initials: H
authors.lastname: Suh
authors.forename: Scott R
authors.initials: SR
authors.lastname: Whitlow
authors.forename: James C
authors.initials: JC
authors.lastname: Fleming
authors.forename: Brianna C
authors.initials: BC
authors.lastname: Monroe
authors.forename: David N
authors.initials: DN
authors.lastname: Ciccone
authors.forename: Catherine
authors.initials: C
authors.lastname: Yan
authors.forename: Katerina
authors.initials: K
authors.lastname: Vlasakova
authors.forename: David M
authors.initials: DM
authors.lastname: Livingston
authors.forename: David O
authors.initials: DO
authors.lastname: Ferguson
authors.forename: Ralph
authors.initials: R
authors.lastname: Scully
authors.forename: Frederick W
authors.initials: FW
authors.lastname: Alt
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000906:Antibodies; D019313:BRCA1 Protein / Q000235:genetics; D001483:Base Sequence; D015153:Blotting, Western; D002843:Chromatin / Q000235:genetics; D004249:DNA Damage; D017931:DNA Primers; D019398:Genes, BRCA1; D014644:Genetic Variation; D006657:Histones / Q000172:deficiency / Q000235:genetics / Q000528:radiation effects*; D051379:Mice; D018345:Mice, Knockout; D009842:Oligopeptides / Q000737:chemistry / Q000276:immunology; D010766:Phosphorylation; D016133:Polymerase Chain Reaction; D011839:Radiation, Ionizing; D013234:Stem Cells / Q000166:cytology / Q000528:radiation effects*
chemical_list: D000906:Antibodies; D019313:BRCA1 Protein; D002843:Chromatin; D017931:DNA Primers; D006657:Histones; D009842:Oligopeptides