title: Differential regulation of short- and long-tract gene conversion between sister chromatids by Rad51C.
abstract: The Rad51 paralog Rad51C has been implicated in the control of homologous recombination. To study the role of Rad51C in vivo in mammalian cells, we analyzed short-tract and long-tract gene conversion between sister chromatids in hamster Rad51C(-/-) CL-V4B cells in response to a site-specific chromosomal double-strand break. Gene conversion was inefficient in these cells and was specifically restored by expression of wild-type Rad51C. Surprisingly, gene conversions in CL-V4B cells were biased in favor of long-tract gene conversion, in comparison to controls expressing wild-type Rad51C. These long-tract events were not associated with crossing over between sister chromatids. Analysis of gene conversion tract lengths in CL-V4B cells lacking Rad51C revealed a bimodal frequency distribution, with almost all gene conversions being either less than 1 kb or greater than 3.2 kb in length. These results indicate that Rad51C plays a pivotal role in determining the "choice" between short- and long-tract gene conversion and in suppressing gene amplifications associated with sister chromatid recombination.
authors.affiliation: Department of Medicine, Harvard Medical School, Beth Israel Deaconess Medical Center, Boston, MA 02215, USA.
authors.forename: Ganesh
authors.initials: G
authors.lastname: Nagaraju
authors.forename: Shobu
authors.initials: S
authors.lastname: Odate
authors.forename: Anyong
authors.initials: A
authors.lastname: Xie
authors.forename: Ralph
authors.initials: R
authors.lastname: Scully
mesh_terms: D000818:Animals; D002460:Cell Line; D002842:Chromatids / Q000235:genetics / Q000378:metabolism*; D006224:Cricetinae; D003434:Crossing Over, Genetic; D004249:DNA Damage; D004260:DNA Repair; D005785:Gene Conversion; D017930:Genes, Reporter; D007527:Isoenzymes / Q000235:genetics / Q000378:metabolism; D051135:Rad51 Recombinase / Q000235:genetics / Q000378:metabolism*; D012854:Sister Chromatid Exchange
chemical_list: D007527:Isoenzymes; D051135:Rad51 Recombinase