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A novel TBP‐associated factor of SL1 functions in RNA polymerase I transcription
Author(s) -
Gorski Julia J,
Pathak Shalini,
Panov Kostya,
Kasciukovic Taciana,
Panova Tanya,
Russell Jackie,
Zomerdijk Joost CBM
Publication year - 2007
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 - 10.1038/sj.emboj.7601601
Subject(s) - biology , rna polymerase ii , transcription factor ii d , transcription factor ii f , rna polymerase i , rna polymerase , transcription (linguistics) , polymerase , genetics , rna polymerase ii holoenzyme , general transcription factor , sigma factor , transcription factor ii b , microbiology and biotechnology , rna , promoter , dna , gene expression , gene , linguistics , philosophy
In mammalian RNA polymerase I transcription, SL1, an assembly of TBP and associated factors (TAFs), is essential for preinitiation complex formation at ribosomal RNA gene promoters in vitro . We provide evidence for a novel component of SL1, TAF I 41 ( MGC5306 ), which functions in Pol I transcription. TAF I 41 resides at the rDNA promoter in the nucleolus and co‐purifies and co‐immunoprecipitates with SL1. TAF I 41 immunodepletion from nuclear extracts dramatically reduces Pol I transcription; addition of SL1 restores the ability of these extracts to support Pol I transcription. In cells, siRNA‐mediated decreased expression of TAF I 41 leads to loss of SL1 from the rDNA promoter in vivo , with concomitant loss of Pol I from the rDNA and reduced synthesis of the pre‐rRNA. Extracts from these cells support reduced levels of Pol I transcription; addition of SL1 to the extracts raises the level of Pol I transcription. These data suggest that TAF I 41 is integral to transcriptionally active SL1 and imply a role for SL1, including the TAF I 41 subunit, in Pol I recruitment and, therefore, preinitiation complex formation in vivo .