Uncoupling Promoter Opening from Start-Site Scanning.
Mol Cell
; 59(1): 133-8, 2015 Jul 02.
Article
em En
| MEDLINE
| ID: mdl-26073544
ABSTRACT
Whereas RNA polymerase II (Pol II) transcription start sites (TSSs) occur about 30-35 bp downstream of the TATA box in metazoans, TSSs are located 40-120 bp downstream in S. cerevisiae. Promoter melting begins about 12 bp downstream in all eukaryotes, so Pol II is presumed to "scan" further downstream before starting transcription in yeast. Here we report that removal of the kinase complex TFIIK from TFIIH shifts the TSS in a yeast system upstream to the location observed in metazoans. Conversely, moving the normal TSS to an upstream location enables a high level of TFIIK-independent transcription in the yeast system. We distinguish two stages of the transcription initiation process bubble formation by TFIIH, which fills the Pol II active center with single-stranded DNA, and subsequent scanning downstream, also driven by TFIIH, which requires displacement of the initial bubble. Omission of TFIIK uncouples the two stages of the process.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Saccharomyces cerevisiae
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RNA Polimerase II
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Proteínas de Saccharomyces cerevisiae
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Sítio de Iniciação de Transcrição
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Fator de Transcrição TFIIH
Idioma:
En
Ano de publicação:
2015
Tipo de documento:
Article