Cooperative clamp-mediated promoter recognition by poxviral RNA polymerase and its TBP/TFIIB-like partner.

ABSTRACT: The recruitment of RNA polymerase to gene promoters is a critical step in gene expression. For RNA polymerase II, this process is initiated by TBP and TFIIB, with homologs of these TBP/TFIIB pairs found in all known multi-subunit RNA polymerase systems. Here, we describe a mode of promoter recognition by the poxviral intermediate transcription factor 3, VITF-3. This heterodimeric factor comprises an atypical TBP/TFIIB pair forming a stable ring structure inert towards DNA in the absence of viral RNA polymerase. Promoter recognition instead requires concerted VITF-3 and viral RNA polymerase binding, as shown by cryo-EM analysis of the intermediate pre-initiation complex. During the formation of this complex, viral RNA polymerase facilitates ring opening and loading of VITF-3 onto the promot

SUBMITTER: Jungwirth S 

PROVIDER: S-EPMC12917281 | biostudies-literature | 2026 Feb

REPOSITORIES: biostudies-literature