rna聚合酶ii啟動轉錄需要70多種多肽的活性。協調這些活動的蛋白質是基礎轉錄因子tfiid，它與核心啟動子結合以正確定位聚合酶，充當組裝其余轉錄復合物的支架，并充當調控信號的通道。tfiid由tata結合蛋白（tbp）和一組進化上保守的蛋白質（tbp相關因子或taf）組成。tafs可能參與基礎轉錄，充當協同激活因子，在啟動子識別中發揮作用，或修飾一般轉錄因子（gtfs），以促進復雜的組裝和轉錄起始。這個基因編碼tfiid的最大亞單位。該亞單位與包含轉錄起始位點的核心啟動子序列結合。它還與激活因子和其他轉錄調節因子結合，這些相互作用影響轉錄起始的速度。該亞單位在n-末端和c-末端含有兩個獨立的蛋白激酶結構域，但也具有乙酰轉移酶活性，可作為泛素激活/結合酶。該基因突變導致肌張力障礙3，扭轉，X連鎖，一種肌張力障礙性帕金森病。該基因的選擇性剪接導致多個轉錄變體。該基因是復雜轉錄單元（taf1/dyt3）的一部分，其中一些轉錄變體與taf1共享外顯子以及其他下游dyt3外顯子。[由RefSeq提供，2013年10月]
Initiation of transcription by RNA polymerase II requires the activities of more than 70 polypeptides. The protein that coordinates these activities is the basal transcription factor TFIID, which binds to the core promoter to position the polymerase properly, serves as the scaffold for assembly of the remainder of the transcription complex, and acts as a channel for regulatory signals. TFIID is composed of the TATA-binding protein (TBP) and a group of evolutionarily conserved proteins known as TBP-associated factors or TAFs. TAFs may participate in basal transcription, serve as coactivators, function in promoter recognition or modify general transcription factors (GTFs) to facilitate complex assembly and transcription initiation. This gene encodes the largest subunit of TFIID. This subunit binds to core promoter sequences encompassing the transcription start site. It also binds to activators and other transcriptional regulators, and these interactions affect the rate of transcription initiation. This subunit contains two independent protein kinase domains at the N- and C-terminals, but also possesses acetyltransferase activity and can act as a ubiquitin-activating/conjugating enzyme. Mutations in this gene result in Dystonia 3, torsion, X-linked, a dystonia-parkinsonism disorder. Alternative splicing of this gene results in multiple transcript variants. This gene is part of a complex transcription unit (TAF1/DYT3), wherein some transcript variants share exons with TAF1 as well as additional downstream DYT3 exons. [provided by RefSeq, Oct 2013]