Specificity
NC2 (negative cofactor 2) is a dimeric histone-fold complex that represses RNA polymerase II transcription through binding to TBP and inhibiting the transcription factors TFIIA and TFIIB. NC2 consists of two subunits, termed NC2a and NC2, and these subunits dimerize and bind to TBP-promoter complexes via histone fold domains of the H2A-H2B type. NC2 associates with promoters in a manner that correlates with transcriptional activity and with occupancy by basal transcription factors. NC2 binds directly to DNA, and the binding of NC2 to TBP-promoter complexes affects the conformation of DNA, and results in the inhibition of TFIIB.
