Which of the following is a promoter element in eukaryotes?

• A. TATA box and CAAT box
• B. -35 TTGACA and -10 TATAAT
• C. GC box and Pribnow box
• D. Kozak sequence and polyadenylation signal

Answer: (A)

Promoter elements in eukaryotes are DNA sequences that help recruit RNA polymerase II and the general transcription machinery to start transcription. The TATA box sits about 25–30 bases upstream of the transcription start site and helps assemble the preinitiation complex by binding TBP, a component of TFIID, guiding the polymerase to the right spot. The CAAT box is located further upstream and provides binding sites for transcription factors that boost transcription, increasing promoter strength. Together, these elements define a classic eukaryotic promoter and set the stage for initiating transcription accurately.

The other options mix contexts that don’t describe eukaryotic promoter elements. The -35 and -10 motifs are bacterial promoter signals recognized by sigma factors, not eukaryotic transcription machinery. The GC box is a regulatory element in some promoters, but the presence of a bacterial Pribnow box in that option shows it’s not a purely eukaryotic promoter element set. The Kozak sequence relates to translation initiation on the mRNA, and the polyadenylation signal marks mRNA processing after transcription, not transcription initiation.