Question

RNA pol II promoter: Which of the following core promoter elements is present in both TATAA-less promoters and in promoters that contain a DPE?

-3 (DPE)
-none
-1 (TATA)
- 2 (Initiator)
-all

Answer 1

The core promoter element present in both TATAA-less promoters and in promoters containing a DPE is the Initiator (Inr) (Option 2). The Inr is essential for transcription initiation, functioning with or without other promoter elements like the TATA box.

Step-by-step explanation:

The core promoter element present in both TATAA-less promoters and in promoters that contain a DPE (Downstream Promoter Element) is the Initiator (Inr).

The Inr encompasses the transcription start site and is a vital component of the core promoter that can function independently of the TATA box in directing the transcriptional machinery to initiate transcription.

While promoters can have distinct features like a TATA box, DPE, or other regulatory sequences, the Inr element is a common feature that can initiate transcription even in the absence of the TATA box.

Hence, the correct answer is Option 2. Initiator.