Plant-specific regulation of replication protein A2 (OsRPA2) from rice during the cell cycle and in response to ultraviolet light exposure

DNA replication is a process that is highly conserved among eukaryotes. Nonetheless, little is known about the proteins involved in it in plants. Replication protein A (RPA) is a heterotrimeric, single-stranded DNA-binding protein with several functions in DNA metabolism in humans and yeast and supposedly also in plants. Here we report on the regulation of OsRPA2, the 32-kDa subunit of RPA from rice (Oryza sativa L.). We found conserved regulation mechanisms at the level of gene expression between animal and plant RPA2 genes and distinct features of OsRPA2 regulation at the level of protein expression. Unlike in animals or in yeast, protein abundance in rice was regulated in a cell cycle phase-specific manner and was altered after UV-C light exposure. On the other hand, post-translational modification through phosphorylation did not appear to play a pivotal role in rice as it does in animal cells. Our results indicate that plant-specific mechanisms of regulation have evolved for RPA2 within the generally well-conserved process of DNA replication, suggesting specific requirements for regulation of DNA metabolism in plants as compared to other eukaryotes.