Question

Which RNA polymerase is not affected by α-amanitin, the toxin of the poisonous mushroom, Amanita phalloides?

• A. RNA polymerase I
• B. RNA polymerase II
• C. RNA polymerase III
• D. RNA polymerase II and III

Hint:

Remember that α-amanitin specifically targets RNA polymerase II.

Answer 1

The Correct Option is A

Step 1: Concept
RNA polymerases and their sensitivity to α-amanitin

Step 2: Meaning
Understanding the specificities of different RNA polymerases, particularly in relation to their susceptibility or resistance to inhibition by α-amanitin.

Step 3: Analysis
α-amanitin is a known inhibitor of RNA polymerase II. It specifically targets this enzyme, which is crucial for eukaryotic mRNA synthesis. Given that it does not affect RNA polymerase I and III, these enzymes must have alternative mechanisms or structures that resist its inhibitory effects.

Step 4: Conclusion
Among the options provided, only RNA polymerase I is unaffected by α-amanitin. Final Answer: (A)