Document Detail


Oxidative stress induces cell cycle-dependent Mre11 recruitment, ATM and Chk2 activation and histone H2AX phosphorylation.
MedLine Citation:
PMID:  18418078     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
DNA damage response recruits complex molecular machinery involved in DNA repair, arrest of cell cycle progression, and potentially in activation of apoptotic pathway. Among the first responders is the Mre11- (MRN) complex of proteins (Mre11, Rad50, Nbs1), essential for activation of ATM; the latter activates checkpoint kinase 2 (Chk2) and phosphorylates histone H2AX. In the present study the recruitment of Mre11 and phosphorylation of ATM, Chk2 and H2AX (gammaH2AX) detected immunocytochemically were measured by laser scanning cytometry to assess kinetics of these events in A549 cells treated with H(2)O(2). Recruitment of Mre11 was rapid, peaked at 10 min of exposure to the oxidant, and was of similar extent in all phases of the cell cycle. ATM and Chk2 activation as well as H2AX phosphorylation reached maximum levels after 30 min of treatment with H(2)O(2); the extent of phosphorylation of each was most prominent in S-, less in G(1)-, and the least in G(2)M- phase cells. A strong correlation between activation of ATM and Chk2, measured in the same cells, was seen in all phases of the cycle. In untreated cells activated Chk2 and Mre11 were distinctly present in centrosomes while in interphase cells they had characteristic punctate nuclear localization. The punctate expression of activated Chk2 both in untreated and H(2)O(2) treated cells was accentuated when measured as maximal pixel rather than integrated value of immunofluorescence (IF) per nucleus, and was most pronounced in G(1) cells, likely reflecting the function of Chk2 in activating Cdc25A. Subpopulations of G(1) and G(2)M cells with strong maximal pixel of Chk2-Thr68(P) IF in association with centrosomes were present in untreated cultures. Cytometric multiparameter assessment of the DNA damage response utilizing quantitative image analysis that allows one to measure inhomogeneity of fluorochrome distribution (e.g., maximal pixel) offers unique advantage in studies of the response of different cell constituents in relation to cell cycle position.
Authors:
Hong Zhao; Frank Traganos; Anthony P Albino; Zbigniew Darzynkiewicz
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Publication Detail:
Type:  Comparative Study; Journal Article; Research Support, N.I.H., Extramural     Date:  2008-03-18
Journal Detail:
Title:  Cell cycle (Georgetown, Tex.)     Volume:  7     ISSN:  1551-4005     ISO Abbreviation:  Cell Cycle     Publication Date:  2008 May 
Date Detail:
Created Date:  2008-06-09     Completed Date:  2008-09-15     Revised Date:  2011-11-02    
Medline Journal Info:
Nlm Unique ID:  101137841     Medline TA:  Cell Cycle     Country:  United States    
Other Details:
Languages:  eng     Pagination:  1490-5     Citation Subset:  IM    
Affiliation:
Brander Cancer Research Institute and Department of Pathology, New York Medical College, Valhalla, New York 10595, USA.
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MeSH Terms
Descriptor/Qualifier:
Cell Cycle / physiology*
Cell Cycle Proteins / metabolism*
Cell Line, Tumor
DNA Damage*
DNA-Binding Proteins / metabolism*
Enzyme Activation / physiology
Histones / metabolism*
Humans
Hydrogen Peroxide
Immunohistochemistry
Kinetics
Laser Scanning Cytometry
Oxidative Stress / physiology*
Phosphorylation
Protein-Serine-Threonine Kinases / metabolism*
Tumor Suppressor Proteins / metabolism*
Grant Support
ID/Acronym/Agency:
CA 28704/CA/NCI NIH HHS; R01 CA028704-29/CA/NCI NIH HHS
Chemical
Reg. No./Substance:
0/Cell Cycle Proteins; 0/DNA-Binding Proteins; 0/H2AFX protein, human; 0/Histones; 0/MRE11A protein, human; 0/Tumor Suppressor Proteins; 7722-84-1/Hydrogen Peroxide; EC 2.7.1.11/checkpoint kinase 2; EC 2.7.11.1/Protein-Serine-Threonine Kinases; EC 2.7.11.1/ataxia telangiectasia mutated protein
Comments/Corrections

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