TAF1B
Domain
Although it shares weak sequence similarity with GTF2B/TFIIB, displays a similar subdomain organization as GTF2B/TFIIB, with a N-terminal zinc finger, a connecting region (composed of B-reader and B-linker regions), followed by 2 cyclin folds. The RRN7-type zinc finger plays an essential postrecruitment role in Pol I transcription at a step preceding synthesis of the first 40 nucleotides (PubMed:21921198, PubMed:21921199).
Function
Component of RNA polymerase I core factor complex that acts as a GTF2B/TFIIB-like factor and plays a key role in multiple steps during transcription initiation such as pre-initiation complex (PIC) assembly and postpolymerase recruitment events in polymerase I (Pol I) transcription. Binds rDNA promoters and plays a role in Pol I recruitment as a component of the SL1/TIF-IB complex and, possibly, directly through its interaction with RRN3.
Sequence Similarities
Belongs to the RRN7/TAF1B family.
Cellular localization
- Nucleus
- Nucleolus
Alternative names
TATA box-binding protein-associated factor RNA polymerase I subunit B, RNA polymerase I-specific TBP-associated factor 63 kDa, TATA box-binding protein-associated factor 1B, Transcription initiation factor SL1/TIF-IB subunit B, TAFI63, TBP-associated factor 1B, TAF1B