Characterization of the RNA chaperone activity of Cms1 protein

초록

CMS1 is a putative protein of unknown function that may participate in rRNA processing and ribosome assembly. It was originally identified as a multi-copy suppressor gene for mcm10, which is implicated to be involved in replication initiation. It is well conserved from yeast to human and dispensable for yeast cell viability. In this study, we found that RNA annealing activity is intrinsically associated with Cms1 protein. Saccharomyces cerevisiae and human Cms1 protein was isolated in their recombinant forms in order to determine their RNA annealing activities. The purified proteins showed strong RNA annealing activities comparable to that of eIF1A, whose RNA annealing activity was characterized in our laboratory. The activity was highly specific for RNA and the single-stranded DNAs with the same sequences were not annealed at all by Cms1 proteins. We also found that Cms1 formed a stable complex with a short double-stranded RNA but not with single-stranded RNA in gel mobility shift assays. The function of Cms1 protein was discussed on the basis of the proteins that interact with Cms1 in Saccharomyces cerevisiae.