Impact of Amino Acid Substitutions in Two Functional Domains of Ku80:DNA-Damage-Sensing Ability of Ku80 and Survival after Irradiation

Journal of Veterinary Medical Science

Yasutomo YUTOKU¹  Aki KOIKE¹  Manabu KOIKE¹ 

[1] DNA Repair Gene Res., National Institute of Radiological Sciences, 4�?9�?1 Anagawa, Inage-ku, Chiba 263�?8555, Japan

关键词: anticancer treatment;    cell death;    γH2AX;    Ku70;    Ku80;   

DOI  :  10.1292/jvms.13-0283

学科分类：兽医学

来源: Japanese Society of Veterinary Science

【 摘 要 】

References(27)Various chemotherapeutic drugs, such as etoposide, and ionizing radiation (IR)have been clinically applied for the treatment of many types of animal and humanmalignancies. IR and chemotheraputic drugs kill tumor cells mainly by inducing DNAdouble-strand breaks (DSBs). On the other hand, unrepaired or incorrectly repaired DSBscan lead to chromosomal truncations and translocations, which can contribute to thedevelopment of cancer in humans and animals. Thus, it is important to clarify themolecular mechanisms underlying the chemosensitivity or radiosensitivity of mammaliancells in order to develop medical treatments and next-generation chemotherapeutic drugsfor cancer. Previously, we established and analyzed cell lines stably expressing chimericconstructs of EGFP and the wild-type Ku80 (XRCC5) protein or its mutant protein to whichmutations were introduced by the site-directed mutagenesis. We found that the Ku70(XRCC6)-binding-site mutations (A453H/V454H) of Ku80 and nuclear localization signal(NLS)-dysfunctional mutations (K565A/K566A/K568A) affected the ability to complementetoposide sensitivity. In this study, we examined the radiosensitivity of these celllines. We found that either or both amino acid substitutions in two functional domains ofKu80, i.e., Ku70-binding-site mutations (A453H/V454H) and NLS-dysfunctional mutations(K565A/K566A/K568A), affect the ability to complement radiosensitivity. Moreover, thesemutations in the two domains of Ku80 affect the DSB-sensing ability of Ku80. Theseinformation and Ku80 mutant cell lines used might be useful for the study of not only thedynamics and function of Ku80, but also the molecular mechanism underlying the cellularresponse to IR and chemotherapeutic drugs in mammalian cells.

【 授权许可】

Unknown