Practice question

TAFs, TBP-associated factors, are integral components of TFIID assembling with TBP via histone-fold dimerization domains mimicking H3-H4 octamer structure and wrapping DNA. Human TFIID includes TAF1 largest with acetyltransferase and kinase activity recognizing initiator element, TAF2, TAF4, TAF6, TAF9 interacting with downstream promoter element, TAF3 recognizing H3K4 trimethylation. TAFs function as coactivators bridging enhancer-bound activators to basal machinery, with bromodomains binding acetylated histone tails and PHD fingers reading methylation marks, thereby integrating chromatin signaling into transcription initiation decisions at specific promoters spatially.