Determination and analysis of site-specific 125I decay-induced DNA double-strand break end-group structures.

Abstract Datta, K., Weinfeld, M., Neumann, R. D. and Winters, T.A. Determination and Analysis of Site-Specific 125I Decay-Induced DNA Double-Strand Break End-Group Structures. Radiat. Res. 167, 152–166 (2007). End groups contribute to the structural complexity of radiation-induced DNA double-strand breaks (DSBs). As such, end-group structures may affect a cell's ability to repair DSBs. The 3′-end groups of strand breaks caused by γ radiation, or oxidative processes, under oxygenated aqueous conditions have been shown to be distributed primarily between 3′-phosphoglycolate and 3′-phosphate, with 5′-phosphate ends in both cases. In this study, end groups of the high-LET-like DSBs caused by 125I decay were investigated. Site-specific DNA double-strand breaks were produced in plasmid pTC27 in the presence or absence of 2 M DMSO by 125I-labeled triplex-forming oligonucleotide targeting. End-group structure was assessed enzymatically as a function of the DSB end to serve as a substrate for ligation and various ...