PMID- 10082553
OWN - NLM
STAT- MEDLINE
DCOM- 19990420
LR  - 20190508
IS  - 0270-7306 (Print)
IS  - 0270-7306 (Linking)
VI  - 19
IP  - 4
DP  - 1999 Apr
TI  - Recruitment of TATA-binding protein-TAFI complex SL1 to the human ribosomal DNA
      promoter is mediated by the carboxy-terminal activation domain of upstream
      binding factor (UBF) and is regulated by UBF phosphorylation.
PG  - 2872-9
AB  - Human rRNA synthesis by RNA polymerase I requires at least two auxiliary factors,
      upstream binding factor (UBF) and SL1. UBF is a DNA binding protein with multiple
      HMG domains that binds directly to the CORE and UCE elements of the ribosomal DNA
      promoter. The carboxy-terminal region of UBF is necessary for transcription
      activation and has been shown to be extensively phosphorylated. SL1, which
      consists of TATA-binding protein (TBP) and three associated factors (TAFIs), does
      not have any sequence-specific DNA binding activity, and its recruitment to the
      promoter is mediated by specific protein interactions with UBF. Once on the
      promoter, the SL1 complex makes direct contact with the DNA promoter and directs 
      promoter-specific initiation of transcription. To investigate the mechanism of
      UBF-dependent transcriptional activation, we first performed protein-protein
      interaction assays between SL1 and a series of UBF deletion mutants. This
      analysis indicated that the carboxy-terminal domain of UBF, which is necessary
      for transcriptional activation, makes direct contact with the TBP-TAFI complex
      SL1. Since this region of UBF can be phosphorylated, we then tested whether this 
      modification plays a functional role in the interaction with SL1. Alkaline
      phosphatase treatment of UBF completely abolished the ability of UBF to interact 
      with SL1; moreover, incubation of the dephosphorylated UBF with nuclear extracts 
      from exponentially growing cells was able to restore the UBF-SL1 interaction. In 
      addition, DNase I footprinting analysis and in vitro-reconstituted transcription 
      assays with phosphatase-treated UBF provided further evidence that UBF
      phosphorylation plays a critical role in the regulation of the recruitment of SL1
      to the ribosomal DNA promoter and stimulation of UBF-dependent transcription.
FAU - Tuan, J C
AU  - Tuan JC
AD  - Department of Molecular Microbiology and Immunology and Norris Comprehensive
      Cancer Center, University of Southern California, School of Medicine, Los
      Angeles, California 90033, USA.
FAU - Zhai, W
AU  - Zhai W
FAU - Comai, L
AU  - Comai L
LA  - eng
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
PL  - United States
TA  - Mol Cell Biol
JT  - Molecular and cellular biology
JID - 8109087
RN  - 0 (DNA, Ribosomal)
RN  - 0 (DNA-Binding Proteins)
RN  - 0 (Pol1 Transcription Initiation Complex Proteins)
RN  - 0 (TATA-Box Binding Protein)
RN  - 0 (Transcription Factors)
RN  - 0 (transcription factor UBF)
RN  - 0 (transcription initiation factor TIF-IB)
RN  - EC 2.7.7.6 (RNA Polymerase I)
SB  - IM
MH  - Binding Sites
MH  - Cell Nucleus
MH  - DNA, Ribosomal/*genetics
MH  - DNA-Binding Proteins/*metabolism
MH  - HeLa Cells
MH  - Humans
MH  - Phosphorylation
MH  - *Pol1 Transcription Initiation Complex Proteins
MH  - Promoter Regions, Genetic
MH  - Protein Binding
MH  - RNA Polymerase I/metabolism
MH  - Subcellular Fractions
MH  - TATA-Box Binding Protein
MH  - Transcription Factors/*metabolism
MH  - *Transcriptional Activation
PMC - PMC84080
EDAT- 1999/03/19 00:00
MHDA- 1999/03/19 00:01
CRDT- 1999/03/19 00:00
PHST- 1999/03/19 00:00 [pubmed]
PHST- 1999/03/19 00:01 [medline]
PHST- 1999/03/19 00:00 [entrez]
AID - 10.1128/mcb.19.4.2872 [doi]
PST - ppublish
SO  - Mol Cell Biol. 1999 Apr;19(4):2872-9. doi: 10.1128/mcb.19.4.2872.