DBP5P, A CYTOSOLIC RNA HELICASE, IS REQUIRED FOR POLY(A)(+) RNA EXPORT

The DBP5 gene encodes a putative RNA helicase of unknown function in t he yeast Saccharomyces cerevisiae, It is shown here that Dbp5p is an A TP-dependent RNA helicase required for polyadenylated [poly(A)(+)] RNA export. Surprisingly, Dbp5p is present predominantly, if not exclusiv ely, in the cytoplasm, and is highly enriched around the nuclear envel ope. This observation raises the possibility that Dbp5p may play a rol e in unloading or remodeling messenger RNA particles (mRNPs) upon arri val in the cytoplasm and in coupling mRNP export and translation. The functions of Dbp5p are likely to be conserved, since its potential hom ologues can be found in a variety of eukaryotic cells.