A serine kinase regulates intracellular localization of splicing factors in the cell cycle
Abstract
SMALL nuclear ribonucleoprotein particles (snRNPs) and non-snRNP splicing factors containing a serine/arginine-rich domain (SR proteins) concentrate in `speckles' in the nucleus of interphase cells1. It is believed that nuclear speckles act as storage sites for splicing factors while splicing occurs on nascent transcripts2. Splicing factors redistribute in response to transcription inhibition3,4 or viral infection5, and nuclear speckles break down and reform as cells progress through mitosis6. We have now identified and cloned a kinase, SRPK1, which is regulated by the cell cycle and is specific for SR proteins; this kinase is related to a Caenorhabditis elegans kinase and to the fission yeast kinase Dskl (ref. 7). SRPK1 specifically induces the disassembly of nuclear speckles, and a high level of SRPK1 inhibits splicing in vitro. Our results indicate that SRPK1 may have a central role in the regulatory network for splicing, controlling the intranuclear distribution of splicing factors in interphase cells, and the reorganization of nuclear speckles during mitosis.
- Publication:
-
Nature
- Pub Date:
- June 1994
- DOI:
- 10.1038/369678a0
- Bibcode:
- 1994Natur.369..678G