Question

Which of the following enzyme is associated with the mitochondrial DNA synthesis?

• A. DNA Pol $\alpha$
• B. DNA Pol $\beta$
• C. DNA Pol $\gamma$
• D. DNA Pol $\delta$

Hint:

Remember the localization:
Nuclear replication/repair $\rightarrow$ Polymerases $\alpha$, $\beta$, $\delta$, $\epsilon$.
Mitochondrial replication/repair $\rightarrow$ Only Polymerase $\gamma$.

Answer 1

The Correct Option is C

Step 1: Understanding the Concept:
Eukaryotic cells contain multiple specialized DNA polymerases categorized into different families (A, B, X, Y) based on their structural homology and subcellular localization.
Detailed Explanation:
Let us analyze the localization and primary functions of the given DNA polymerases:
- DNA Polymerase $\alpha$ ($\text{Pol }\alpha$): Located in the nucleus.
It forms a complex with primase (the pol-$\alpha$-primase complex) and is responsible for initiating eukaryotic nuclear DNA replication by synthesizing short RNA-DNA primers on both the leading and lagging strands.
- DNA Polymerase $\beta$ ($\text{Pol }\beta$): Located in the nucleus.
It belongs to Family X and is primarily involved in short-patch base excision repair (BER) of damaged nuclear DNA.
- DNA Polymerase $\gamma$ ($\text{Pol }\gamma$): Located exclusively within the mitochondria.
It is a Family A DNA polymerase and is the sole DNA polymerase responsible for both the replication and repair of the mitochondrial genome (mtDNA).
- DNA Polymerase $\delta$ ($\text{Pol }\delta$): Located in the nucleus.
It is a high-fidelity polymerase responsible for the elongation of the lagging strand during nuclear DNA replication.

Step 2: Final Answer:
DNA Polymerase $\gamma$ is the enzyme associated with mitochondrial DNA synthesis. This corresponds to option (C).