Nucleocytoplasmic RNA transport.

Abstract

During the past decade, it has become evident that, in eukaryotes, RNA molecules undergo a complex series of chemical modifications after transcription and before translation and that some of these modifications coincide with alterations in subcellular distribution. There is growing evidence that these posttranscriptional events, both at the level of the RNA molecule (“processing”) and at the whole-cell level (“transport”), are of great biological importance. Posttranscriptional RNA processing has been thoroughly and frequently reviewed over the past few years, and (although many controversies remain to be resolved) a coherent body of thought has existed in the field at least since publication of the review by Perry (1976). However, RNA transport, the cellbiological counterpart of processing, has been much less thoroughly reviewed, and despite the steady accumulation of experimental data, the field lacks a coherent body of thought. The review by Webb et al. (1981) is comprehensive and argues cogently for a special messenger RNA (mRNA) transport mechanism, susceptible to regulating influences including hormones, and for abnormalities at the locus of RNA transport in a number of pathological conditions. As the first complete survey of the field, however, it offers no general hypothesis about mechanism. An article on the cytoplasmic regulation of eukaryotic gene expression by Lichtenstein et al. (1981) contains much that is relevant to RNA transport, but, being concerned with the assessment of an interesting speculative model, does not address itself critically to the experimental basis of the data to which it refers.