Nuclear actin and myosin I are required for RNA polymerase I transcription.
Nat Cell Biol
; 6(12): 1165-72, 2004 Dec.
Article
en En
| MEDLINE
| ID: mdl-15558034
ABSTRACT
The 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.
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Banco de datos:
MEDLINE
Asunto principal:
Transcripción Genética
/
ARN Polimerasa I
/
ARN Ribosómico
/
Núcleo Celular
/
Actinas
/
Miosina Tipo I
Límite:
Humans
Idioma:
En
Revista:
Nat Cell Biol
Año:
2004
Tipo del documento:
Article
País de afiliación:
República Checa