Replication Protein A (RPA1a) is Required for Meiotic and Somatic DNA Repair but is Dispensable ...
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Replication Protein A (RPA1a) is Required for Meiotic and Somatic DNA Repair but is Dispensable for DNA Replication and Homologous Recombination in Rice Yuxiao Chang , Liang Gong , Wenya Yuan , Xingwang Li , Guoxing Chen , Xianghua Li , Qifa Zhang , and Changyin Wu National Key Laboratory of Crop Genetic Improvement and National Center of Plant Gene Research (Wuhan), Huazhong Agricultural University, Wuhan 430070, China. Abstract: Replication protein A (RPA), a highly conserved single-stranded DNA-binding protein in eukaryotes, is a stable complex comprising three subunits termed RPA1, RPA2 and RPA3. RPA is required for multiple processes in DNA metabolism such as replication, repair and homologous recombination in yeast and human. Most eukaryotic organisms, including fungi, insects and vertebrates, have only a single RPA gene that encodes each RPA subunits. Arabidopsis and rice, however, possess multiple copies of an RPA gene. Rice has three paralogs each of RPA1 and RPA2, and one for RPA3. Previous studies have established their biochemical interactions in vitro and in vivo, but little is known about their exact function in rice. We examined the function of OsRPA1a in rice using a T-DNA insertional mutant. The osrpa1a mutants had a normal phenotype during vegetative growth but were sterile at the reproductive stage. Cytological examination confirmed that no embryo sac formed in female meiocytes and that abnormal chromosomal fragmentation occurred in male meiocytes after anaphase I. Compared with wild type, the osrpa1a mutant showed no visible defects in mitosis and chromosome pairing and synapsis during meiosis. In addition, the osrpa1a mutant was hypersensitive to UV-C irradiation and the DNA-damaging agents mitomycin C (MMC) and methyl methanesulfonate (MMS). Thus, our data suggest that OsRPA1a plays an essential role in DNA repair but may not participate in, or at least is dispensable for, DNA replication and homologous recombination in rice.