Architecture of the yeast RNA polymerase II open complex and regulation of activity by TFIIF.

Publication Type:

Journal Article

Source:

Molecular and cellular biology, Volume 32, Issue 1, p.25 (2012)

Keywords:

2012, Alcohol Oxidoreductases, Aminohydrolases, Base Sequence, Basic Sciences Division, Center-Authored Paper, Consortium Authored Paper, Gene Expression Regulation, Fungal, Models, Molecular, Molecular Sequence Data, November 2011, Promoter Regions, Genetic, Pyrophosphatases, RNA Polymerase II, Saccharomyces cerevisiae, Saccharomyces cerevisiae Proteins, TATA-Box Binding Protein, Transcription Factor TFIIB, Transcription Factors, TFII, TRANSCRIPTIONAL ACTIVATION

Abstract:

To investigate the function and architecture of the open complex state of RNA polymerase (Pol) II, S. cerevisiae minimal open complexes were assembled using a series of heteroduplex HIS4 promoters, TBP, TFIIB, and Pol II. The yeast system demonstrates great flexibility in the position of active open complexes, spanning 30-80 base pairs downstream from TATA, consistent with the transcription start site scanning behavior of yeast Pol II. TFIIF unexpectedly modulates activity of the open complexes, either repressing or stimulating initiation. The response to TFIIF was dependent on the sequence of the template strand within the single stranded bubble. Mutations in the TFIIB reader and linker region, which were inactive on duplex DNA, were suppressed by the heteroduplex templates, showing that a major function of the TFIIB reader and linker is in initiation or stabilization of single stranded DNA. Probing the architecture of the minimal open complexes with TFIIB-FeBABE derivatives showed that the TFIIB core domain is surprisingly positioned away from Pol II, and addition of TFIIF repositions the TFIIB core domain to the Pol II wall domain. Together, our results show an unexpected architecture of minimal open complexes and regulation of activity by TFIIF and the TFIIB core domain.