Cookies on this website
We use cookies to ensure that we give you the best experience on our website. If you click 'Continue' we'll assume that you are happy to receive all cookies and you won't see this message again. Click 'Find out more' for information on how to change your cookie settings.

DNA double strand breaks (DSBs) are amongst the most deleterious lesions induced within the cell following exposure to ionizing radiation. Mammalian cells repair these breaks predominantly via the nonhomologous end joining pathway which is active throughout the cell cycle and is error prone. The alternative pathway for repair of DSBs is homologous recombination (HR) which is error free and active during S- and G2/M-phases of the cell cycle. We have utilized near-infrared laser radiation to induce DNA damage in individual mammalian cells through multiphoton excitation processes to investigate the dynamics of single cell DNA damage processing. We have used immunofluorescent imaging of gamma-H2AX (a marker for DSBs) in mammalian cells and investigated the colocalization of this protein with ATM, p53 binding protein 1 and RAD51, an integral protein of the HR DNA repair pathway. We have observed persistent DSBs at later times postlaser irradiation which are indicative of DSBs arising at replication, presumably from UV photoproducts or clustered damage containing single strand breaks. Cell cycle studies have shown that in G1 cells, a significant fraction of multiphoton laser-induced prompt DSBs persists for > 4 h in addition to those induced at replication.

Original publication

DOI

10.1111/j.1751-1097.2008.00378.x

Type

Journal article

Journal

Photochem Photobiol

Publication Date

11/2008

Volume

84

Pages

1506 - 1514

Keywords

Animals, Cell Cycle, Cell Line, Cricetinae, Cricetulus, DNA, DNA Breaks, Double-Stranded, DNA Breaks, Single-Stranded, DNA Replication, Kinetics, Photons, Rad51 Recombinase