RNA TRANSPORT

RNA molecules synthesized in the nucleus are transported to their site s of function throughout the eukaryotic cell by specific transport pat hways. This review focuses on transport of messenger RNA, small nuclea r RNA, ribosomal RNA, and transfer RNA between the nucleus and the cyt oplasm. The general molecular mechanisms involved in nucleocytoplasmic transport of RNA are only beginning to be understood. However, during the past few years, substantial progress has been made. A major theme that emerges from recent studies of RNA transport is that specific si gnals mediate the transport of each class of RNA, and these signals ar e provided largely by the specific proteins with which each RNA is ass ociated.