Quantification of DNA damage by PFGE: development of an analytical approach to correct for the background distribution

Abstract

Purpose : To analyse the currently existing methods to infer the extent of cellular DNA damage induced by ionizing radiation when the pulsed field gel electrophoresis (PFGE) technique is used. Results and conclusions : PFGE is currently the method of choice for the measurement of radiation-induced double-strand breaks (dsb). For accurate determination of both the yields and distributions of breaks, separation of a large range of fragment sizes is required. In the conventional analysis of PFGE experiments, the background distribution of fractionated molecules is, normally, simply subtracted from the irradiated measured distribution, for each molecular weight region available. This work shows that this approach may lead to incorrect estimation of the breakage frequencies. An alternative approach based on correcting the fitting functions for the actual nonrandom damage present in the control unirradiated samples has been developed.