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.

中文翻译：

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拟南芥RAD51样基因的分子克隆和表征。

同源重组是维持和变异基因组的重要过程。在真核生物中，Rad52上位基团蛋白在减数分裂重组和/或同源重组修复中起主要作用。类似Rad51的蛋白质，例如酵母中的Rad55和Rad57，在促进同源配对和链交换反应的多聚Rad51的装配或稳定中发挥作用。我们从拟南芥中克隆了两个名为AtXRCC3和AtRAD51C的RAD51样基因。AtXRCC3和AtRAD51C都表达了两个选择性剪​​接的转录本，而AtRAD51C产生了两种不同大小的同工型，一种是长的（AtRAD51Calpha），另一种是短的（AtRAD51Cbeta）。这些基因的预测蛋白质序列显示了RecA / Rad51家族的特征。尤其是ATP结合基序周围的氨基酸非常保守。在各种组织中检测到AtXRCC3和AtRAD51C的转录本，在花蕾中的表达水平最高。两种基因的表达均通过γ射线辐射诱导。酵母双杂交检测结果表明拟南芥Rad51家族蛋白形成复合物，可参与减数分裂重组和/或同源重组修复。