In a typical eukaryotic gene, the start site of transcription is found immediately downstream of which element?

• A. Enhancer
• B. Core promoter
• C. TATA box
• D. Polyadenylation site

Answer: (B)

The start of transcription is set by the promoter region that sits directly upstream of the gene. The core promoter is the short DNA stretch that recruits the basal transcription machinery and fixes where RNA polymerase II begins. Transcription begins at the precise site downstream of this promoter, often at a defined +1 position, with elements like the TATA box helping to position the polymerase. Enhancers can boost how much transcription occurs by looping to the promoter but don’t determine the exact start site. The polyadenylation site, on the other hand, marks the end of the transcript, not where initiation happens.