Cloning of murine RNA polymerase I-specific TAF factors: Conserved interactions between the subunits of the species-specific transcription initiation factor TIF-IB/SL1
AUTOR(ES)
Heix, Jutta
FONTE
The National Academy of Sciences of the USA
RESUMO
Promoter selectivity for all three classes of eukaryotic RNA polymerases is brought about by multimeric protein complexes containing TATA box binding protein (TBP) and specific TBP-associated factors (TAFs). Unlike class II- and III-specific TBP–TAF complexes, the corresponding murine and human class I-specific transcription initiation factor TIF-IB/SL1 exhibits a pronounced selectivity for its homologous promoter. As a first step toward understanding the molecular basis of species-specific promoter recognition, we cloned the cDNAs encoding the three mouse pol I-specific TBP-associated factors (TAFIs) and compared the amino acid sequences of the murine TAFIs with their human counterparts. The four subunits from either species can form stable chimeric complexes that contain stoichiometric amounts of TBP and TAFIs, demonstrating that differences in the primary structure of human and mouse TAFIs do not dramatically alter the network of protein–protein contacts responsible for assembly of the multimeric complex. Thus, primate vs. rodent promoter selectivity mediated by the TBP–TAFI complex is likely to be the result of cumulative subtle differences between individual subunits that lead to species-specific properties of RNA polymerase I transcription.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=19985Documentos Relacionados
- The species-specific RNA polymerase I transcription factor SL-1 binds to upstream binding factor.
- TATA box-binding protein (TBP) is a constituent of the polymerase I-specific transcription initiation factor TIF-IB (SL1) bound to the rRNA promoter and shows differential sensitivity to TBP-directed reagents in polymerase I, II, and III transcription factors.
- Acetylation of TAFI68, a subunit of TIF-IB/SL1, activates RNA polymerase I transcription
- Localization of the yeast RNA polymerase I-specific subunits
- The conserved core domain of the human TATA binding protein is sufficient to assemble the multisubunit RNA polymerase I-specific transcription factor SL1.
