Initiation of transcription by RNA polymerase I requires the formation of a complex composed of the TATA-binding protein (TBP) and three TBP-associated factors (TAFs) specific for RNA polymerase I. This complex, known as SL1, binds to the core promoter of ribosomal RNA genes to position the polymerase properly and acts as a channel for regulatory signals. This gene encodes the largest SL1-specific TAF. Multiple alternatively spliced transcript variants encoding different isoforms have been identified. [provided by RefSeq, Jul 2011]
Function:
Component of the transcription factor SL1/TIF-IB complex, which is involved in the assembly of the PIC (preinitiation complex) during RNA polymerase I-dependent transcription. The rate of PIC formation probably is primarily dependent on the rate of association of SL1/TIF-IB with the rDNA promoter. SL1/TIF-IB is involved in stabilization of nucleolar transcription factor 1/UBTF on rDNA. Formation of SL1/TIF-IB excludes the association of TBP with TFIID subunits. Recruits RNA polymerase I to the rRNA gene promoter via interaction with RRN3.
Subunit:
Component of the transcription factor SL1/TIF-IB complex, composed of TBP and at least TAF1A, TAF1B, TAF1C and TAF1D. In the complex interacts directly with TBP, TAF1A and TAF1B. Interaction of the SL1/TIF-IB subunits with TBP excludes interaction of TBP with the transcription factor IID (TFIID) subunits. Interacts with MYC and RRN3. Interacts with p53/TP53; the interaction prevents the association of SL1/TIF-IB with UBTF and represses RNA polymerase I transcription.
Subcellular Location:
Nucleus.
Post-translational modifications:
Phosphorylated upon DNA damage, probably by ATM or ATR.
SWISS:
Q15572
Gene ID:
9013
Database links:
Entrez Gene: 9013 Human
Omim: 604905 Human
SwissProt: Q15572 Human
Unigene: 153022 Human
|
|
