A novel TBP-associated factor of SL1 functions in RNA polymerase I transcription

作者：Gorski Julia J; Pathak Shalini; Panov Kostya; Kasciukovic Taciana; Panova Tanya; Russell Jackie; Zomerdijk Joost C B M^*

来源：The EMBO Journal, 2007, 26(6): 1560-1568.

DOI：10.1038/sj.emboj.7601601

• ribosomal RNA synthesis
• RNA polymerase I
• RNA polymerase recruitment
• SL1
• TAF(I)41

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. TAFI41 resides at the rDNA promoter in the nucleolus and co-purifies and co-immunoprecipitates with SL1. TAFI41 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 TAFI41 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 TAFI41 is integral to transcriptionally active SL1 and imply a role for SL1, including the TAFI41 subunit, in Pol I recruitment and, therefore, preinitiation complex formation in vivo.

• 出版日期2007-3-21