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轉錄因子iid（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TBP，TATA結合蛋白tbp的一個顯著特征是n端有一長串谷氨酰胺。蛋白質的這一區域調節C末端的DNA結合活性，DNA結合的調節影響轉錄復合物的形成和轉錄起始的速度編碼多聚谷氨酰胺通道的CAG重復的數目通常為25-42，重復到45-66的數目的增加增加了聚谷氨酰胺串的長度，并與脊髓小腦共濟失調17相關，該神經退行性疾病被歸類為多聚谷氨酰胺病。已經發現了兩個編碼不同亞型的轉錄變體。
Initiation of transcription by RNA polymerase II requires the activities of more than 70 polypeptides. The protein that coordinates these activities is transcription factor IID (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 TBP, the TATA-binding protein. A distinctive feature of TBP is a long string of glutamines in the N-terminus. This region of the protein modulates the DNA binding activity of the C terminus, and modulation of DNA binding affects the rate of transcription complex formation and initiation of transcription. The number of CAG repeats encoding the polyglutamine tract is usually 25-42, and expansion of the number of repeats to 45-66 increases the length of the polyglutamine string and is associated with spinocerebellar ataxia 17, a neurodegenerative disorder classified as a polyglutamine disease. Two transcript variants encoding different isoforms have been found for this gene.