Homologous DNA pairing and strand exchange

Stable Identifier
Gallus gallus
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Genetic recombination and the repair of double strand DNA breaks in Saccharomyces cerevisiae require Rad51, a homologue of the Escherichia coli RecA protein. In vitro, Rad51 binds DNA to form an extended nucleoprotein filament and catalyzes the ATP-dependent exchange of DNA between molecules with homologous sequences. Vertebrate Rad51 is essential for cell proliferation. The core reactions of homologous pairing, strand-transfer, exchange and annealing require RAD51 and its paralogs. These paralogs show high degree of divergence from RAD51 as well as from each other although the individual paralogs are well conserved between human and chicken cells. It has been suggested that Rad51 and Rad52 act cooperatively. In chicken RAD52 (-/-) cells, intrachromosomal recombination as measured by immunoglobulin gene conversion, and radiation-induced Rad51 nuclear focus formation (which is a putative intermediate step during recombinational repair), are unaffected. However, RAD52 has a clear role in genetic recombination because the frequency of targeted integration is reduced in RAD52 (-/-) cells. Although RAD52 can partially substitute for XRCC3 (one of the RAD51 paralogs), the rad52 xrcc3 double-mutant cells are non viable and exhibit extensive chromosomal breaks, indicating an overlapping (but non-reciprocal) role for RAD52 and XRCC3 in repairing DNA double-strand breaks. RAD54 interacts with RAD51 and plays an important role in DNA strand opening activities that occurs during strand invasion. RAD18 is also involved in the actual homologous recombination reaction along with its role in post-replication repair.

Literature References
PubMed ID Title Journal Year
16923963 Role for RAD18 in homologous recombination in DT40 cells

Sz?ts, D, Simpson, LJ, Kabani, S, Yamazoe, M, Sale, JE

Mol Cell Biol 2006
9774659 Homologous recombination, but not DNA repair, is reduced in vertebrate cells deficient in RAD52

Yamaguchi-Iwai, Y, Sonoda, E, Buerstedde, JM, Bezzubova, O, Morrison, C, Takata, M, Shinohara, A, Takeda, S

Mol Cell Biol 1998
11574483 Rad52 partially substitutes for the Rad51 paralog XRCC3 in maintaining chromosomal integrity in vertebrate cells

Fujimori, A, Tachiiri, S, Sonoda, E, Thompson, LH, Dhar, PK, Hiraoka, M, Takeda, S, Zhang, Y, Reth, M, Takata, M

EMBO J 2001
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