Identification of TATA-binding protein-free TAFII-containing complex subunits suggests a role in nucleosome acetylation and signal transduction

Recently we identified a novel human (h) multiprotein complex, called TATA-binding protein (TBP)-free TAF(II)containing complex (TFTC), which is able to nucleate RNA polymerase II transcription and can mediate transcriptional activation. Here we demonstrate that TFTC, similar to other TBP-free TAF(II), complexes (yeast SAGA, hSTAGA, and hPCAF) contains the acetyltransferase hGCN5 and is able to acetylate histones in both a free and a nucleosomal context. The recently described TRRAP cofactor for oncogenic transcription factor pathways was also characterized as a TFTC subunit, Furthermore, we identified four other previously uncharacterized subunits of TFTC: hADA3, hTAF(II)150, hSPT3, and hPAF65 beta. Thus, the polypeptide composition of TFTC suggests that TFTC is recruited to chromatin templates by activators to acetylate histones and thus may potentiate initiation and activation of transcription.