Retinoblastoma Protein Disrupts Interactions Required for RNA Polymerase III Transcription
AUTOR(ES)
Sutcliffe, Josephine E.
FONTE
American Society for Microbiology
RESUMO
The retinoblastoma protein (RB) has been shown to suppress RNA polymerase (Pol) III transcription in vivo (R. J. White, D. Trouche, K. Martin, S. P. Jackson, and T. Kouzarides, Nature 382:88–90, 1996). This regulation involves interaction with TFIIIB, a multisubunit factor that is required for the expression of all Pol III templates (C. G. C. Larminie, C. A. Cairns, R. Mital, K. Martin, T. Kouzarides, S. P. Jackson, and R. J. White, EMBO J. 16:2061–2071, 1997; W.-M. Chu, Z. Wang, R. G. Roeder, and C. W. Schmid, J. Biol. Chem. 272:14755–14761, 1997). However, it has not been established why RB binding to TFIIIB results in transcriptional repression. For several Pol II-transcribed genes, RB has been shown to inhibit expression by recruiting histone deacetylases, which are thought to decrease promoter accessibility. We present evidence that histone deacetylases exert a negative effect on Pol III activity in vivo. However, RB remains able to regulate Pol III transcription in the presence of the histone deacetylase inhibitor trichostatin A. Instead, RB represses by disrupting interactions between TFIIIB and other components of the basal Pol III transcription apparatus. Recruitment of TFIIIB to most class III genes requires its binding to TFIIIC2, but this can be blocked by RB. In addition, RB disrupts the interaction between TFIIIB and Pol III that is essential for transcription. The ability of RB to inhibit these key interactions can explain its action as a potent repressor of class III gene expression.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=102177Documentos Relacionados
- Distinct Mechanisms for Repression of RNA Polymerase III Transcription by the Retinoblastoma Tumor Suppressor Protein
- Casein kinase II is required for efficient transcription by RNA polymerase III.
- The Retinoblastoma Tumor Suppressor Protein Targets Distinct General Transcription Factors To Regulate RNA Polymerase III Gene Expression
- Mechanism of repression of RNA polymerase I transcription by the retinoblastoma protein.
- Transcription factor IIIB generates extended DNA interactions in RNA polymerase III transcription complexes on tRNA genes.