Species-specific variation of RPA-interacting protein (RIP) splice isoforms

Abstract

Replication Protein A (RPA) is a single stranded DNA-binding protein involved in DNA metabolic activities such as replication, repair, and recombination. RPA-Interacting Protein alpha (RIP alpha) was originally identified as a nuclear transporter of RPA in Xenopus. The human RIP alpha gene encodes several splice isoforms, of which hRIP alpha and hRIP beta are the major translation products in vivo. However, limited information is available about the alternative splicing of RIP alpha in eukaryotes, apart from that in humans. In this study, we examined the alternative splicing of RIP alpha in the Drosophila, Xenopus, and mouse system. We showed that the number of splice isoforms of RIP alpha was species-specific, and displayed a tendency to increase in higher eukaryotes. Moreover, a mouse ortholog of hRIP beta, mRIP beta 2, was not SUMOylated, in contrast to hRIP beta. Based on these results, we suggest that the RIP alpha gene gains more splice isoforms and additional modifications after molecular evolution. [BMB reports 2009; 42(1): 22-27]