Minimal promoter systems reveal the importance of conserved residues in the B-finger of human transcription factor IIB.

ABSTRACT: The "B-finger" of transcription factor IIB (TFIIB) is highly conserved and believed to play a role in the initiation process. We performed alanine substitutions across the B-finger of human TFIIB, made change-of-charge mutations in selected residues, and substituted the B-finger sequence from other organisms. Mutant proteins were examined in two minimal promoter systems (containing only RNA polymerase II, TATA-binding protein, and TFIIB) and in a complex system, using TFIIB-immunodepleted HeLa cell nuclear extract (NE). Mutations in conserved residues located on the sides of the B-finger had the greatest effect on activity in both minimal promoter systems, with mutations in residues Glu-51 and Arg-66 eliminating activity. The double change-of-charge mutant (E51R:R66E) did not show activity

SUBMITTER: Thompson NE 

PROVIDER: S-EPMC2757179 | biostudies-literature | 2009 Sep

REPOSITORIES: biostudies-literature