The isolation and characterization of the genes involved in the maintenance of genome integrity

2014 Fiscal Year Final Research Report

• Project/Area Number: 23570012
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Genetics/Genome dynamics
• Research Institution: National Institute of Radiological Sciences
• Principal Investigator: SUGAYA Kimihiko 独立行政法人放射線医学総合研究所, 放射線防護研究センター, 主任研究員 (80280741)
• Co-Investigator(Renkei-kenkyūsha): TSUJI Hideo 放射線医学総合研究所, 福島復興支援本部, 専門業務員 (40163795)
• Research Collaborator: ISHIHARA Yoshie ; INOUE Sonoe
• Project Period (FY): 2011-04-28 – 2015-03-31
• Keywords: 温度感受性変異株 / GFP / 染色体不安定性 / 相補性試験 / DNA複製 / ユビキチン活性化酵素

Outline of Final Research Achievements

A temperature-sensitive (ts) CHO-K1 mutant, tsTM3, exhibits chromosomal instability and cell-cycle arrest in the S to G2 phases with decreased DNA synthesis at the nonpermissive temperature, 39℃. In the present study, we identified a point mutation in a gene encoding ubiquitin activating enzyme, Uba1, isolated from the tsTM3 cells, which led to a Met-to-Ile substitution at amino acid 256 in deduced Uba1 protein. Mutant cells at the nonpermissive temperature showed a significant decrease of Uba1 in the nucleus with decreased ubiquitination activity. This defect in ubiquitination led to significant accumulation of geminin and retention of Cdt1, resulting in an inappropriate balance between Cdt1 and geminin. Both Cdt1 and its inhibitor, geminin, are crucial regulators of the licensing of DNA replication. Uba1 plays an important role in the nucleus, and a ts mutation found in tsTM3 cells appears to result in the loss of localization of Uba1 in the nucleus.

Free Research Field

分子生物学