Which protein recognizes the TATA box to position RNA polymerase II for transcription initiation?

• A. TBP recognizes the TATA box to position RNA polymerase II for transcription initiation.
• B. TFIID binds to RNA to start translation.
• C. RNA polymerase II recognizes TATA box directly.
• D. Histone deacetylases recognize TATA box.

Answer: (A)

The protein that recognizes the TATA box to position RNA polymerase II for transcription initiation is the TATA-binding protein, a key subunit of the transcription factor complex that binds promoter DNA. TBP binds specifically to the TATA sequence and induces a bend in the DNA, which helps assemble the preinitiation complex by attracting the other general transcription factors (TFIIA, TFIIB, TFIIF, TFIIE, TFIIH) and RNA polymerase II at the correct start site. This positioning is essential for accurate transcription initiation. The full complex TFIID includes TBP and other components, but the direct recognition of the TATA box is performed by TBP itself. RNA polymerase II cannot recognize the TATA box on its own, and histone deacetylases, which modify chromatin to repress transcription, do not recognize promoter motifs like the TATA box.