Destiny of unspliced retroviral RNA: ribosome and/or virion?

Abstract

A longstanding unknown in viral RNA biology is the relationship between translation and packaging of genomic RNA. For retroviruses, an extensive body of work has characterized nuclear export of the unspliced genome-length transcript (5, 8, 15), but the cytoplasmic trafficking of the RNA has remained relatively undefined. An elegant experimental approach that was initiated over 25 years ago has been updated and extended to human retroviruses during the last year. A consensus on the relationship between translation and packaging of retroviral RNA has been reached. An unexpected finding was that retroviruses have adapted two divergent approaches to manage the cytoplasmic fate of genomic RNA. This minireview introduces the interdependent relationship between translation and packaging of retroviral RNA, postulates models of retroviral RNA trafficking in the cytoplasm, summarizes experimental results that address the models, and discusses the recent consensus.