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National Institute of Environmental Health Sciences

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Your Environment. Your Health.

Publication Detail

Title: Ionizing radiation-dependent gamma-H2AX focus formation requires ataxia telangiectasia mutated and ataxia telangiectasia mutated and Rad3-related.

Authors: Friesner, Joanna D; Liu, Bo; Culligan, Kevin; Britt, Anne B

Published In Mol Biol Cell, (2005 May)

Abstract: The histone variant H2AX is rapidly phosphorylated at the sites of DNA double-strand breaks (DSBs). This phosphorylated H2AX (gamma-H2AX) is involved in the retention of repair and signaling factor complexes at sites of DNA damage. The dependency of this phosphorylation on the various PI3K-related protein kinases (in mammals, ataxia telangiectasia mutated and Rad3-related [ATR], ataxia telangiectasia mutated [ATM], and DNA-PKCs) has been a subject of debate; it has been suggested that ATM is required for the induction of foci at DSBs, whereas ATR is involved in the recognition of stalled replication forks. In this study, using Arabidopsis as a model system, we investigated the ATR and ATM dependency of the formation of gamma-H2AX foci in M-phase cells exposed to ionizing radiation (IR). We find that although the majority of these foci are ATM-dependent, approximately 10% of IR-induced gamma-H2AX foci require, instead, functional ATR. This indicates that even in the absence of DNA replication, a distinct subset of IR-induced damage is recognized by ATR. In addition, we find that in plants, gamma-H2AX foci are induced at only one-third the rate observed in yeasts and mammals. This result may partly account for the relatively high radioresistance of plants versus yeast and mammals.

PubMed ID: 15772150 Exiting the NIEHS site

MeSH Terms: Arabidopsis Proteins/chemistry; Arabidopsis Proteins/genetics; Arabidopsis Proteins/metabolism*; Arabidopsis/cytology; Arabidopsis/genetics; Arabidopsis/metabolism*; Arabidopsis/radiation effects*; Ataxia Telangiectasia Mutated Proteins; Cell Cycle Proteins/genetics; Cell Cycle Proteins/metabolism*; Cell Division; Cell Line; DNA Repair; DNA Replication; Genes, Plant; Histones/chemistry; Histones/genetics; Histones/metabolism*; Humans; Mutation; Phosphorylation; Protein-Serine-Threonine Kinases/genetics; Protein-Serine-Threonine Kinases/metabolism*; Radiation Tolerance; Species Specificity

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