ABSTRACT
Ataxia-telangiectasia (A-T) is an autosome recessive genetic disease, being characteristic of the special clinical performances like progressive cerebellar degeneration, high radiosensitivity, immunodeficiency, genomic instability, early-maturing, high incidence rate of tumor. AT mutation (ATM) gene protein encoding involves in cell cycle regulation, DNA damage signaling conduction and repair and the maintenance of chromosome stability. When cells are ionizing radiated, the signal conduction paths mediated by ATM kinase are activated so as to identify and repair the damaged DNA. In the fibroblast of AT patients, the loss of ATM kinase activity caused by ATM gene mutation results in AT cells cannot be repaired the DNA damages caused by damage factors like irradiation, expressing high readiosensitivity and chromosomal instability [Lavin 1997, Meyn 1999]. We adopted hypoxanthine phospho-ribosyltransferase (hprt) locus mutation analysis and Cytokinesis-Block micronucleus method (CBMN) to study the high radiosensitivity of AT cells. Hprt gene locates in the end of X chromosome q, being a locus which is sensitive to ionizing radiation, so it is easy and rapid to detect the gene locus damages of genetic material caused by ionizing radiation [Mazin 2009, Czaja 2012]. Cytokinesis-Block micronucleus method was put forward by Fenech et al [Fenech 1985] in 1985, which can simply and easily measure chromosomal damage.
