Induction of Premature Chromosome Condensation (PCC) by Calyculin A for biodosimetry

B iological dosimetry of ionizing radiation is generally performed by scoring dicentrics and/or translocations in chromosome from peripheral blood lymphocytes (pbl) at the first mitosis following in vitro growth stimulation. It is well known that after irradiation, in this procedure mitotic index is low in some individuals, so the scored mitoses might not be representative of the exposed cell population. For these reasons premature chromosome condensation (PCC) was introduced by Johnson and Rao (1970) following fusion of an interphase with a mitotic cell (Johnson and Rao 1070) 1970). With the use of this method makes it is possible to distinguish individual chromosomes at different stages of the cell cycle. Thus, it has been used to study the formation of chromosomal aberrations shortly after irradiation and the kinetics of chromosome break rejoining (Pantelias and Maillie 1985). This technique is considered as a potent biodosimetric tool (Blakely et al. 1995) since it is probably one of the most sensitive methods for analyzing initial chromosomal damage after irradiation (Sipi et al. 2000). At present, PCC can be induced by two methods, cell fusion and using chemicals. In cell fusion method, CHO mitotic cells with high promoting factor (MPF) are fused to interphase cells by polyethylene glycol (PEG) or Sendi virus. After staining, chromosome elements appear as single chromatids and can be discriminated easily from the CHO mitotic chromosomes in human interphase G0/G1 PCC spread Induction of Premature Chromosome Condensation (PCC) by Calyculin A for biodosimetry