Analysis of radiation-sensitive cells derived from Japanese patient.

Abstract

The lymphoblast cells from a Japanese patient, characterized by severe combined immunodeficiency, growth retardation and congenital malformation, showed high incidence of both of spontaneous and radiation-induced chromosome aberrations. Here, we show that the cultured skin fibroblast cells from a patient are markedly sensitive to ionizing radiation. Western blot analysis revealed normal expression of NBS1, underlying gene of Nijmegen breakage syndrome, which shares the common features with the Japanese patient. The patient cells also showed normal expression of Mre11/Rad50, components of complex with NBS1, and formed their radiation-induced foci at the level similar to that of normal cells. Furthermore, the cells showed the normal phosphorylation of Chk2 kinase after irradiation. These results indicated that the syndrome reported here is unlikely ataxia-telangiectasia and Nijmegen breakage syndromes, suggesting a novel radiation sensitive disease.