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A minimal RNA polymerase III transcription system
Author(s) -
Kassavetis George A.,
Letts Garth A.,
Geiduschek E. Peter
Publication year - 1999
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.1093/emboj/18.18.5042
Subject(s) - biology , rna polymerase ii , transcription factor ii d , transcription (linguistics) , polymerase , rna polymerase , rna polymerase i , rna polymerase ii holoenzyme , microbiology and biotechnology , genetics , rna dependent rna polymerase , rna , dna , gene expression , gene , promoter , linguistics , philosophy
Transcription factor (TF) IIIB recruits RNA polymerase (pol) III for specific initiation of transcription. All three subunits of TFIIIB, TBP, Brf (the TFIIB‐related subunit) and B″, are required for transcription of supercoiled and linear duplex DNA, but we show here that B″ is non‐essential on a promoter that has been partly pre‐opened by unpairing a short segment of the transcription bubble. These findings expose a striking similarity between transcriptional initiation by pol II, pol III and bacterial RNA polymerases: a preformed single‐stranded DNA bubble upstream of the transcriptional start removes the dependence of pol II on TFIIE, TFIIH and ATP hydrolysis, and the dependence of pol III on B″; the favored placement of the transcription bubble for B″‐independent transcription by pol III overlaps a DNA segment that interacts sequence specifically as single‐stranded DNA with the σ 70 initiation subunit of Escherichia coli RNA polymerase holoenzyme.