Transcription factor TFIIIB component B'' (IPR030701)

Short name: TFIIIB_B''

Overlapping homologous superfamilies


Family relationships


Transcription by RNA polymerase III (pol III) is a complex molecular process orchestrated by the two main transcription factors, TFIIIB and TFIIIC. The TFIIIB complex can be recruited by TFIIIC to upstream DNA and form an exceptionally kinetically stable TFIIIB-DNA complex, which then recruits the Pol III enzymatic complex and helps maintain it for multiple transcription cycles in a process called facilitated recycling [PMID: 11433012]. Saccharomyces cerevisiae TFIIIB is a complex of three subunits, the TATA box-binding protein TBP, the TFIIB-related factor BRF, and the beta'' protein.

This entry represents the component beta'' from yeast and mammals. Beta'' contacts DNA both upstream and downstream of the TATA box, involving the highly conserved SANT domain region [PMID: 10497245]. It functions in assembly of the pre-initiation complex and may serves as a scaffold protein that provides the stability for the TFIIIB-DNA complex [PMID: 11433012]. The human homologue of yeast component beta'' has been identified and is required for transcription of both TATA-less and snRNA-type RNA polymerase III promoters [PMID: 11040218].

GO terms

Biological Process

GO:0006383 transcription by RNA polymerase III

Molecular Function

GO:0001026 TFIIIB-type transcription factor activity

Cellular Component

GO:0000126 transcription factor TFIIIB complex

Contributing signatures

Signatures from InterPro member databases are used to construct an entry.