Increased ionizing radiation sensitivity and genomic instability in the absence of histone H2AX.
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.
Bassing
Craig H
CH
Howard Hughes Medical Institute, Department of Genetics, Children's Hospital, Boston, MA 02115, USA.
Chua
Katrin F
KF
Sekiguchi
JoAnn
J
Suh
Heikyung
H
Whitlow
Scott R
SR
Fleming
James C
JC
Monroe
Brianna C
BC
Ciccone
David N
DN
Yan
Catherine
C
Vlasakova
Katerina
K
Livingston
David M
DM
Ferguson
David O
DO
Scully
Ralph
R
Alt
Frederick W
FW
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*
D000906:Antibodies; D019313:BRCA1 Protein; D002843:Chromatin; D017931:DNA Primers; D006657:Histones; D009842:Oligopeptides