Linked Life Data

15655354

Source:http://linkedlifedata.com/resource/pubmed/id/15655354

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2
pubmed:dateCreated
2005-4-22
pubmed:abstractText
Damage to DNA that engenders double-strand breaks (DSBs) triggers phosphorylation of histone H2AX on Ser-139. Expression of phosphorylated H2AX (gammaH2AX) can be revealed immunocytochemically; the intensity of gammaH2AX immunofluorescence (IF) measured by cytometry was reported to correlate with the frequency of DSBs induced by X-ray radiation or by DNA damaging antitumor drugs. The aim of the present study was to measure expression of gammaH2AX following exposure of HeLa and HL-60 cells to a wide range of doses of UV-B light (6.1 J/m(2)-3.45 kJ/m(2)) and using multiparameter flow and laser scanning cytometry (LSC) to correlate DNA damage with cell cycle phase and induction of apoptosis. In both cell lines, the highest degree of H2AX phosphorylation induced by UV was seen in S-phase cells, particularly during early portion of S. In cells that did not replicate DNA (G(1), G(2) and M) the degree of H2AX phosphorylation was markedly lower than that in S-phase cells, and was strongly UV dose-dependent. Furthermore, the level of UV-induced gammaH2AX in G(1), G(2) and M was much higher in HeLa- than in HL-60- cells. Apoptotic cells become apparent >2h after exposure to UV and exhibited nearly an order of magnitude higher intensity of gammaH2AX IF than that initially induced by UV; predominantly S-phase cells underwent apoptosis. While the suppression of DNA replication, by aphidicolin prevented the induction of H2AX phosphorylation by UV in most S phase cells, it had no effect on a small cohort of cells that appeared to be entering S-phase, that expressed very high levels of gammaH2AX. Furthermore, aphidicolin itself induced gammaH2AX in early-S phase cells. The induction of gammaH2AX by UV was inhibited, but the incidence of apoptosis increased, by 5 mM caffeine, a known inhibitor of PI-3-related kinases. The data are consistent with the notion that H2AX phosphorylation observed throughout S phase reflects formation of DSBs due to the collision of replication forks with the UV-induced primary DNA lesions. Induction of gammaH2AX in G(1), G(2) and M is likely a response to the primary DSBs generated during UV exposure and/or DNA repair. It is unclear why the latter process was more pronounced in HeLa than in HL-60 cells.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Feb
pubmed:issn
1551-4005
pubmed:author
pubmed:issnType
Electronic
pubmed:volume
4
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
339-45
pubmed:dateRevised
2010-12-3
pubmed:meshHeading
pubmed:year
2005
pubmed:articleTitle
Histone H2AX phosphorylation after cell irradiation with UV-B: relationship to cell cycle phase and induction of apoptosis.
pubmed:affiliation
Brander Cancer Research Institute, New York Medical College, Valhalla, New York, USA.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, N.I.H., Extramural