| RRC ID |
44959
|
| 著者 |
Ohara M, Funyu Y, Ebara S, Sakamoto Y, Seki R, Iijima K, Ohishi A, Kobayashi J, Komatsu K, Tachibana A, Tauchi H.
|
| タイトル |
Mutations in the FHA-domain of ectopically expressed NBS1 lead to radiosensitization and to no increase in somatic mutation rates via a partial suppression of homologous recombination.
|
| ジャーナル |
J Radiat Res
|
| Abstract |
Ionizing radiation induces DNA double-strand breaks (DSBs). Mammalian cells repair DSBs through multiple pathways, and the repair pathway that is utilized may affect cellular radiation sensitivity. In this study, we examined effects on cellular radiosensitivity resulting from functional alterations in homologous recombination (HR). HR was inhibited by overexpression of the forkhead-associated (FHA) domain-mutated NBS1 (G27D/R28D: FHA-2D) protein in HeLa cells or in hamster cells carrying a human X-chromosome. Cells expressing FHA-2D presented partially (but significantly) HR-deficient phenotypes, which were assayed by the reduction of gene conversion frequencies measured with a reporter assay, a decrease in radiation-induced Mre11 foci formation, and hypersensitivity to camptothecin treatments. Interestingly, ectopic expression of FHA-2D did not increase the frequency of radiation-induced somatic mutations at the HPRT locus, suggesting that a partial reduction of HR efficiency has only a slight effect on genomic stability. The expression of FHA-2D rendered the exponentially growing cell population slightly (but significantly) more sensitive to ionizing radiation. This radiosensitization effect due to the expression of FHA-2D was enhanced when the cells were irradiated with split doses delivered at 24-h intervals. Furthermore, enhancement of radiation sensitivity by split dose irradiation was not seen in contact-inhibited G0/G1 populations, even though the cells expressed FHA-2D. These results suggest that the FHA domain of NBS1 might be an effective molecular target that can be used to induce radiosensitization using low molecular weight chemicals, and that partial inhibition of HR might improve the effectiveness of cancer radiotherapy.
|
| 巻・号 |
55(4)
|
| ページ |
690-8
|
| 公開日 |
2014-7-1
|
| DOI |
10.1093/jrr/rru011
|
| PII |
rru011
|
| PMID |
24614819
|
| PMC |
PMC4100003
|
| MeSH |
Animals
Cell Cycle Proteins / chemistry
Cell Cycle Proteins / genetics*
Cell Line
Cricetinae
DNA Breaks, Double-Stranded
DNA Repair / genetics
DNA Repair / radiation effects
HeLa Cells
Homologous Recombination
Humans
Mutation*
Nuclear Proteins / chemistry
Nuclear Proteins / genetics*
Protein Structure, Tertiary
Radiation Tolerance / genetics*
Recombinant Proteins / chemistry
Recombinant Proteins / genetics
|
| IF |
1.95
|
| 引用数 |
2
|
|
WOS 分野
|
BIOLOGY
RADIOLOGY, NUCLEAR MEDICINE & MEDICAL IMAGING
|
| リソース情報 |
| ヒト・動物細胞 |
HeLa |
