Isolation and characterization of Xenopus ATM (X-ATM): expression, localization, and complex formation during oogenesis and early development.

摘要: ATM, the gene product mutated in Ataxia Telangiectasia (A-T) encodes a 350-kDa protein involved regulation of several cellular responses to DNA breaks. We used degenerate PCR-based strategy isolate partial clone X-ATM, Xenopus homologue human ATM. Sequence analysis and confirmed that was most closely related ATM (X-ATM) is 85% identical within kinase domain 71% over carboxyl-terminal half protein. Polyclonal antibodies raised against recombinant X-ATM are highly specific for recognize single polypeptide 370-kDa oocytes, embryos, egg extracts cell line. found expressed maternally eggs as early stage II pre-vitellogenic mRNA were present at relatively constant levels throughout development. Subcellular fractionation showed nuclear both female male germlines. The level did not change meiotic divisions or synchronous mitotic cycles cleavage embryos. In addition, we observe any mobility following γ-irradiation Finally, also demonstrated high molecular weight complex approximately 500 kDa containing other, yet unidentified component(s).