Role of telomere addition in the stabilization of radiation induced DNA breaks

This project concerns the investigation of the role of telomere addition in the healing of radiation induced chromosome breaks and how this molecular mechanism determines the formation and stabilization of chromosome aberrations. To this end, germ line and early embryonic cells (both telomerase competent) will be used. The specific objectives are summarized below: a) To investigate the formation of telomeres at the end of radiation-induced chromosome breaks and acentric fragments in spermatogenic cells of the mouse (mitotic spermatofonia, primary and secondary spermatocytes). b) To investigate the de novo addition of telomeres to the tips of radiation-induced chromosome breaks and acentric fragments in mouse embryos during the early stages of developement (zygotes, two-cell and four-cell embryos). c) To evaluate telomerase activity at the different spermatogenic and embryonic cells of mice is related to the dose of radiation.