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

Abstract

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, posttranslational 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.

ROR1/RPA2A, a Putative Replication Protein A2, Functions in Epigenetic Gene Silencing and in Regulation of Meristem Development inArabidopsis

“…Promoter analysis indicates that ROR1/RPA2A is expressed more highly in root tips, shoot apices, and young leaves but is also detected in other differentiated tissues. This expression pattern is similar to that of rice RPA2 (Marwedel et al, 2003). Eukaryotic DNA replication is restricted to the S phase of the cell cycle.…”

The reduced kinome of Ostreococcus tauri: core eukaryotic signalling components in a tractable model species

“…RPA in turn forms a heterotrimeric complex, which interacts with recombination components to repair DNA double-strand breaks. Unlike DNA-PK, RPA is conserved across eukaryotes, and phosphorylation sites on RPA have been found to be conserved in yeast, metazoa and higher-plants [54]. DNA-PK was also recently shown to be involved in innate immunity against viruses [55].…”

Differential expression of the two distinct replication protein A subunits from Cryptosporidium parvum

“…In several systems, it appears that the phosphorylation of RPA (RPA2, in particular) is intimately involved in this regulation during the cell cycle and in response to DNA damage [Pasion et al, 1994;Brown and Ray, 1997;Wold, 1997;Iftode et al, 1999;Perdigao et al, 1999;Voss et al, 2002;Marwedel et al, 2003]. In protozoa, however, RPA abundance has been demonstrated to fluctuate in a cell-cycle-dependent manner [Brown and Ray, 1997;Voss et al, 2002].…”

“…Expression levels, phosphorylation status, and sub-cellular localization of RPA proteins have been correlated with the onset of DNA replication, responses to DNA damage, and initiation of recombination [Pasion et al, 1994;Wold, 1997;Perdigao et al, 1999;Voss et al, 2002;Marwedel et al, 2003;Binz et al, 2004]. Although different functions for the long and short types of RPA1 proteins have been suggested based on their differential expression patterns and ssDNA-binding properties [Millership and Zhu, 2002;Rider et al, 2005], their true biological roles remained to be elucidated.…”