Nature Cell Biology
6, 1165 - 1172 (2004)
Published online: 21 November 2004; | doi:10.1038/ncb1190
Nuclear actin and myosin I are required for RNA polymerase I transcriptionVlada V. Philimonenko1, 5, Jian Zhao2, 5, Sebastian Iben2, Hana Dingová1, Katarína Kyselá1, Michal Kahle1, Hanswalter Zentgraf3, Wilma A. Hofmann4, Primal de Lanerolle4, Pavel Hozák1
& Ingrid Grummt21
Department of Cell Ultrastructure and Molecular Biology, Institute of Experimental Medicine, Academy of Sciences of the Czech Republic, Prague 14220, Czech Republic. 2
Division of Molecular Biology of the Cell II, German Cancer Research Center, D-69118 Heidelberg, Germany. 3
Applied Tumorvirology, German Cancer Research Center, D-69118 Heidelberg, Germany. 4
Department of Physiology and Biophysics, University of Illinois at Chicago, Chicago IL 60612, USA. 5
These authors contributed equally to this work.
Correspondence should be addressed to Ingrid Grummt i.grummt@dkfz.deThe presence of actin and nuclear myosin I (NMI) in the nucleus suggests a role for these motor proteins in nuclear functions. We have investigated the role of actin and nuclear myosin I (NMI) in the transcription of ribosomal RNA genes (rDNA). Both proteins are associated with rDNA and are required for RNA polymerase I (Pol I) transcription. Microinjection of antibodies against actin or NMI, as well as short interfering RNA-mediated depletion of NMI, decreased Pol I transcription in vivo, whereas overexpression of NMI augmented pre-rRNA synthesis. In vitro, recombinant NMI activated Pol I transcription, and antibodies to NMI or actin inhibited Pol I transcription both on naked DNA and pre-assembled chromatin templates. Whereas actin associated with Pol I, NMI bound to Pol I through the transcription-initiation factor TIF-IA. The association with Pol I requires phosphorylation of TIF-IA at Ser 649 by RSK kinase, indicating a role for NMI in the growth-dependent regulation of rRNA synthesis.
MORE ARTICLES LIKE THIS These links to content published by NPG are automatically generated.
|
