Introduction to the Detection of DNA Strand Breaks
DNA strand breaks, especially single-stranded breaks (SSB), are very commonly found through the life cyde of cells. In fact, SSB have been implicated to play important roles in the regulation of cell proliferation (Stewart et a1.1990), cell differentiation (Appleby and Modak 1977; Farzaneh et a1.1982; Dawson and Lough 1988) and cell death (Gold et al. 1993; Peitsch et al. 1993; Bortner et al. 1995; Hashimoto et al. 1995). Also, in the course of replicative DNA synthesis (Ogawa and Okazaki 1980), DNA repair (Ma et al. 1995) and genetic recombination in meiosis, SSB occur transiently. On the other hand, DNA double-stranded breaks (DSB) were often the results of DNA damages induced by irradiation of ionizing radial rays or by some anti tumor drugs. Recently, however, DSB have been highlighted as a biochemical marker (Wyllie 1980) of apoptosis, the notion of which was introduced by Kerr et al. (1972). Currently, cell death is categorized into two groups; apoptosis and necrosis. Apoptosis, in contrast to necrosis, is morphologically characterized by the special features of chromatin condensation to the nudear periphery and the fragmentation of the cell into apoptotic bodies. More importantly, apoptosis requires the de novo expression of specific genes and so implies that the death can be manipulated artificially.
KeywordsPeripheral Blood Lymphocyte Nick Translation Template Strand Cell BioI Adult Mouse Testis
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