DNA polymerase delta

DNA polymerase delta (Pol δ) is an essential enzyme in eukaryotic cells, playing a critical role in DNA replication and DNA repair. It is a member of the DNA polymerase family, which are responsible for synthesizing new strands of DNA during cell division.

Structure

Pol δ is a heterotetramer, composed of four different subunits: POLD1, POLD2, POLD3, and POLD4. The POLD1 subunit contains the catalytic site of the enzyme, while the other subunits are involved in regulatory functions and interactions with other proteins.

Function

Pol δ is primarily involved in the synthesis of the lagging strand during DNA replication. It works in conjunction with DNA ligase and RNA primase to create Okazaki fragments, short segments of DNA that are later joined together to form the complete strand.

In addition to its role in DNA replication, Pol δ also plays a crucial role in DNA repair. It is involved in several different repair pathways, including base excision repair, nucleotide excision repair, and mismatch repair. In these pathways, Pol δ synthesizes new DNA to replace the damaged section.

Clinical significance

Mutations in the genes encoding the subunits of Pol δ can lead to a variety of diseases. For example, mutations in POLD1 have been associated with colorectal cancer, endometrial cancer, and a form of polymerase proofreading-associated polyposis (PPAP). Mutations in POLD3 have been linked to Meier-Gorlin syndrome, a rare genetic disorder characterized by small stature and ear abnormalities.

See also

• DNA polymerase alpha
• DNA polymerase epsilon
• DNA replication