The ins and outs of HIV Rev

The Rev protein of the human immunodeficiency virus mediates the nuclear export of the intron-containing viral messages. This export is a consequence of the continuous shuttling of HIV Rev between the nucleus and cytoplasm. This shuttling is mediated by a nuclear localization signal and a nuclear export signal contained within Rev. Recently, several factors which are required for the movement of Rev through the nuclear pore have been identified. This review will focus on these factors and their role the nucleocytoplasmic shuttling of HIV Rev.