Rejoining of DNA strand breaks by T4 DNA ligase in mammalian cells.
We have tested the ability of T4 DNA ligase to rejoin radiation-induced DNA strand breaks in living hamster cells (CHO-K1, EM9, xrs-5). T4 DNA ligase was introduced into cells by electroporation prior to x-irradiation. Single- and double-strand breaks were measured by the alkaline comet assay technique, and double-strand breaks (DSBs) were evaluated by the pulsed-field gel electrophoresis method. In the comet assay, the three cell lines showed reduced tail moments following pretreatment with T4 DNA ligase, both directly after irradiation and after repair incubation for 4 h. Similarly, the results obtained from pulsed-field gel electrophoresis showed reduced DSB frequencies after pretreatment with T4 DNA ligase. We conclude that exogeneous T4 ligase contributes to rejoining of radiation-induced strand breaks.
Department of Cell Biology, Faculty of Biology, University of Seville, Avd. Reina Mercedes s/n, 41012 Seville, Spain. salles@us.es
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D000818:Animals; D016466:CHO Cells / Q000145:classification / Q000378:metabolism / Q000528:radiation effects; D006224:Cricetinae; D004247:DNA / Q000187:drug effects* / Q000378:metabolism / Q000528:radiation effects*; D004249:DNA Damage / Q000187:drug effects*; D011088:DNA Ligases / Q000008:administration & dosage* / Q000378:metabolism; D004260:DNA Repair / Q000187:drug effects*; D004277:DNA, Single-Stranded / Q000528:radiation effects; D004307:Dose-Response Relationship, Radiation; D012016:Reference Values; D012680:Sensitivity and Specificity; D013045:Species Specificity
D004277:DNA, Single-Stranded; D004247:DNA; D011088:DNA Ligases