Which protein recognizes the TATA box in many eukaryotic promoters?

• A. TBP (TATA-binding protein).
• B. Sigma factor.
• C. 16S rRNA.
• D. Rho helicase.

Answer: (A)

This question tests how promoter elements are recognized in eukaryotic transcription, specifically which protein binds the TATA box. The TATA box is a DNA motif located about 25–30 bases upstream of the transcription start site, and TBP, the TATA-binding protein, binds this element as part of the transcription factor complex TFIID. TBP’s binding bends the DNA, creating a favorable platform that helps recruit RNA polymerase II and the other general transcription factors to form the preinitiation complex. This makes TBP the best answer. The other proteins have different roles: a bacterial sigma factor recognizes promoter elements in bacteria rather than the TATA box; 16S rRNA is a ribosomal RNA component; and Rho helicase is involved in transcription termination in bacteria.