Study of radiation-induced clustered DNA damage by fluorescence anisotropy measurement based on Förster resonance energy transfer

Abstract

It is well-known that DNA lesions induced by ionizing radiation and chemicals can cause mutation and carcinogenesis. In particular, “clustered damage" site, that is a DNA region with multiple lesions within a few helical turns, is believed to hardly be repaired. This type of damage is considered to be induced around high-LET radiation tracks and at a track-end of secondary electron. However, chemical and spatial details of them are not known. We have developed a methodology for estimating localization of the lesions using fluorescence anisotropy. The fluorescence anisotropy generally decreases with increasing Förster resonance energy transfer (FRET) efficiency. We found that experimentally-obtained anisotropy for the heat-treated DNA correspond to theoretical ones calculated on the basis of exponential distribution. Now we are applying the methodology based on fluorescence anisotropy to liner-formed pUC19 irradiated with radiation such as Co-60 gamma-rays, helium, carbon, and Fe ion beams. The results and the prospective will be discussed.ICRR(International Congress on Radiation Research) 201