Nups take leave of the nuclear envelope to regulate transcription

Abstract

Although components of the nuclear pore complex have been implicated in gene regulation independent of their role at the nuclear envelope, the evidence so far has been indirect. Capelson et al. (2010) and Kalverda et al. (2010) now reveal that certain nucleoporins are actively involved in transcription inside the nucleoplasm of Drosophila cells.

Figure 1. Processes by which nucleoporins regulate gene expression

The figure shows established and putative interactions between nucleoporins (Nups) and various components of the nucleus, including DNA, mRNA, RNA polymerase II (RNAPII), RNA processing and export machineries, histone modifying enzymes; some of these relationships are illustrative and require further confirmation. In Drosophila cells, nucleoporins (Sec13, Nup98, Nup62, Nup50 and mAB414 positive FG-Nups are sequentially recruited to genes undergoing activation and are required for distinct steps of transcription initiation and elongation. Nup88, a nuclear pore complex (NPC) filament protein located on the cytoplasmic side, associates mainly with silent chromatin. NPCs associate preferentially with a subset of genes expressed at a low level. Nucleoporins may also act as a shuttle to bridge transcription and mRNA transport between the inside of the nucleus and the nuclear periphery. During the heat shock response nucleoporins may be required for activation of the heat shock genes and for the transcriptional recovery of silenced but previously transcribed genes.