This entry includes budding yeast Ncb2 and its homologues. Ncb2 is a component of the NC2 complex which represses RNA polymerase II transcription through binding to Spt15/TBP and thereby inhibiting the assembly of the preinitiation complex []. Its human homologue, DR1, associates with DRAP1 through histone fold motifs to form the NC2 complex, which negatively regulates transcription initiation [].This entry also includes proteins from fungi, such as NctB from Neosartorya fumigata and Ncb2 from Candida albicans. NctB forms a complex with NctA, and this complex acts as a general transcriptional cofactor []. In Candida albicans, conditional Ncb2 null mutants have been shown to display decreased susceptibility toward azole and an enhanced transcription of CDR1 [].
A mechanism for repression of class II gene transcription through specific binding of NC2 to TBP-promoter complexes via heterodimeric histone fold domains.