Nucleic Acids Research Advance Access originally published online on April 16, 2008
Nucleic Acids Research 2008 36(10):3226-3234; doi:10.1093/nar/gkn171
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Nucleic Acids Research, 2008, Vol. 36, No. 10 3226-3234
© 2008 The Author(s)
This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/2.0/uk/) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.
Molecular Biology |
Identification of a novel human Rad51 variant that promotes DNA strand exchange
1Department of Biochemistry, School of Medicine, Wonkwang University, Iksan, Jeollabuk-Do 570-749, 2School of Life Sciences and Biotechnology, Korea University, Seoul 136-701, 3Department of Pediatrics, Asan Medical Center, Seoul 138-736 and 4Vestibulocochlear Research Center, School of Medicine, Wonkwang University, Iksan, Jeollabuk-Do 570-749, South Korea
*To whom correspondence should be addressed. Tel: +82 63 850 6795; Fax: +82 63 850 7310; Email: youngkim{at}wku.ac.kr Correspondence may also be addressed to Sang-Yun Choi. Tel: +82 2 3290 3441; Fax: +82 2 927 3091; Email: sychoi{at}korea.ac.kr
Received January 14, 2008. Revised March 24, 2008. Accepted March 25, 2008.
Rad51 plays a key role in the repair of DNA double-strand breaks through homologous recombination, which is the central process in the maintenance of genomic integrity. Five paralogs of the human Rad51 gene (hRad51) have been identified to date, including hRad51B, hRad51C, hRad51D, Xrcc2 and Xrcc3. In searches of additional hRad51 paralogs, we identified a novel hRad51 variant that lacked the sequence corresponding to exon 9 (hRad51-
ex9). The expected amino acid sequence of hRad51-
ex9 showed a frame-shift at codon 259, which resulted in a truncated C-terminus. RT-PCR analysis revealed that both hRad51 and hRad51-
ex9 were prominently expressed in the testis, but that there were subtle differences in tissue specificity. The hRad51-
ex9 protein was detected as a 31-kDa protein in the testis and localized at the nucleus. In addition, the hRad51-
ex9 protein showed a DNA-strand exchange activity comparable to that of hRad51. Taken together, these results indicate that hRad51-
ex9 promotes homologous pairing and DNA strand exchange in the nucleus, suggesting that alternative pathways in hRad51- or hRad51-
ex9-dependent manners exist for DNA recombination and repair.