Question

RNA polymerase II binds to which region of protein-coding genes?

• A. ORF
• B. Promoter
• C. Poly A
• D. Terminator

Hint:

Promoter = The "Landing Pad" for RNA Polymerase.
In prokaryotes, the sigma factor helps the polymerase find the promoter.
In eukaryotes, various transcription factors (TFs) are required to recruit RNA Pol II to the promoter.

Answer 1

The Correct Option is B

Step 1: Understanding the Question:
The question focuses on the initiation phase of transcription in eukaryotes, specifically where the primary enzyme for mRNA synthesis attaches to the DNA.
Detailed Explanation:

• RNA Polymerase II:
In eukaryotes, there are three types of RNA polymerases. RNA Pol II is responsible for transcribing all protein-coding genes into messenger RNA (mRNA).

• The Promoter Region:
For transcription to start, RNA Pol II must recognize and bind to a specific regulatory sequence located upstream ($5'$) of the gene. This region is called the Promoter.
A key feature of many eukaryotic promoters is the TATA box, which helps position the polymerase at the correct start site.

• Analyzing other options:
ORF: This is the region that is actually transcribed and translated; the polymerase travels through it but does not "bind" there to start.
Poly A: Refers to the polyadenylation signal at the $3'$ end of the mRNA; it is involved in termination and stability.
Terminator: The sequence that signals the polymerase to stop transcription and detach from the DNA.

Step 2: Final Answer:
RNA polymerase II binds to the promoter region to initiate the transcription of protein-coding genes.