Untitled

Abstract

Homologous recombination is an essential process for the maintenance and variability of the genome. In eukaryotes, the Rad52 epistasis group proteins serve the main role for meiotic recombination and/or homologous recombinational repair. Rad51-like proteins, such as Rad55 and Rad57 in yeast, play a role in assembly or stabilization of multimeric Rad51 that promotes homologous pairing and strand exchange reactions. We cloned two RAD51-like genes named AtXRCC3 and AtRAD51C from Arabidopsis thaliana. Both AtXRCC3 and AtRAD51C expressed two alternatively spliced transcripts, and AtRAD51C produced two different sizes of isoforms, a long (AtRAD51Calpha) and a short one (AtRAD51Cbeta). The predicted protein sequences of these genes showed characteristic features of the RecA/Rad51 family; especially the amino acids around the ATP-binding motifs were well conserved. The transcripts of AtXRCC3 and AtRAD51C were detected in various tissues, with the highest level of expression in flower buds. Expression of both genes was induced by gamma-ray irradiation. The results of yeast two-hybrid assays suggested that Arabidopsis Rad51 family proteins form a complex, which could participate in meiotic recombination and/or homologous recombinational repair.

The Interplay of RecA-related Proteins and the MND1–HOP2 Complex during Meiosis in Arabidopsis thaliana

“…Many studies have shown that Xrcc3 form a complex with Rad51C, and that this complex may contain Rad51 [10,59,60]. Two-hybrid analyses performed with Arabidopsis sequences confirmed that AtXRCC3 interacts with AtRAD51 [34]. These results indicate that the AtRAD51 and AtXRCC3 proteins cooperate in the same recombination step during meiosis…”

“…However, little is known about their functional relationship and their genetic and physical interactions in Arabidopsis : AtBRCA2 interacts with either AtDMC1 or AtRAD51 [33], and the repair of meiotic DSBs in Atdmc1 mutants is dependent on AtBRCA2 and AtRAD51 [27]. Two-hybrid assays have shown that AtMND1 interacts with AHP2 and that AtXRCC3 interacts with AtRAD51 and AtRAD51C [28,34]. …”

The plant‐specific CDKB 1‐ CYCB 1 complex mediates homologous recombination repair in Arabidopsis

“…RAD51 and its homologs build a small gene family in Arabidopsis similar to other eukaryotes (Lin et al , 2006). Previous studies revealed hypersensitivity of mutants in Arabidopsis RAD51 family members to DNA‐cross‐linking agents such as cisplatin and mitomycin C, as seen, for example, by a reduced number of true leaves formed in rad51b and rad51c mutants in comparison with the wild type (Osakabe et al , 2002, 2005; Bleuyard & White, 2004; Abe et al , 2005; Bleuyard et al , 2005; Li et al , 2005; Charbonnel et al , 2010). Consistent with these reports, we found that the root growth of rad51 mutants is impaired in the presence of cisplatin (Fig 5A–C).…”

Arabidopsis RAD51, RAD51C and XRCC3 proteins form a complex and facilitate RAD51 localization on chromosomes for meiotic recombination

“…Vertebrate Rad51 paralogs interact with one another to form two distinct complexes: BCDX2 and CX3 [52]. Like vertebrates, Arabidopsis has seven RAD51 paralogs, and previous yeast two-hybrid assays have shown that XRCC3 interacts with both RAD51C and RAD51 [41]. However, whether these proteins interact in planta has not been investigated.…”

“…Moreover, RAD51C and XRCC3 also help mediate Holliday junction (HJ) resolution in vitro [40], suggesting a later role in meiotic recombination. A yeast two-hybrid assay demonstrated that the Arabidopsis RAD51 paralogs also interact with each other [41], supporting the idea that RAD51 paralogs function by formation of distinct protein complexes in both animals and plants. However, whether the RAD51 paralogs associate with each other in planta has not been tested.…”