Which DNA polymerase is primarily used in the process of Nick Translation?

Nick translation is a molecular biology technique used to label DNA, where a nick is introduced in the DNA strand, and the DNA polymerase replaces the nucleotides surrounding the nick with labeled nucleotides. The key enzyme in this process is DNA polymerase I.

DNA polymerase I possesses both 5' to 3' polymerase activity, allowing it to synthesize new DNA, and 5' to 3' exonuclease activity, enabling it to remove nucleotides from the existing strand. This combination of activities is crucial for the nick translation procedure, as it allows for the removal of nucleotides at the nick and simultaneous incorporation of new labeled nucleotides in their place.

Other DNA polymerases, while they have significant functions in DNA replication and repair, do not possess the necessary exonuclease activity alongside polymerization to effectively carry out the nick translation process. Therefore, DNA polymerase I is the definitive choice for this technique.