Connecting the transcription site to the nuclear pore: a multi-tether process that regulates gene expression.

It is now well established that the position of a gene within the nucleus can influence the level of its activity. So far, special emphasis has been placed on the nuclear envelope (NE) as a transcriptionally silent nuclear sub-domain. Recent work, however, indicates that peripheral localization is not always associated with repression, but rather fulfills a dual function in gene expression. In particular, in the yeast Saccharomyces cerevisiae, a large number of highly expressed genes and activated inducible genes preferentially associate with nuclear pore complexes (NPCs), a process that is mediated by transient interactions between the transcribed locus and the NPC. Recent studies aimed at unraveling the molecular basis of this mechanism have revealed that maintenance of genes at the NPC involves multiple tethers at different steps of gene expression. These observations are consistent with tight interconnections between transcription, mRNA processing and export into the cytoplasm, and highlight a role for the NPC in promoting and orchestrating the gene expression process. In this Commentary, we discuss the factors involved in active gene anchoring to the NPC and the diverse emerging roles of the NPC environment in promoting gene expression, focusing on yeast as a model organism.