POLG2

Description

The POLG2 (DNA polymerase gamma 2, accessory subunit) is a protein-coding gene located on chromosome 17.

The POLG2 gene encodes a 55 kDa accessory subunit protein that enhances the function of DNA polymerase gamma, encoded by the POLG gene. This protein is crucial for the replication of mitochondrial DNA (mtDNA) and plays a role in the high processivity and salt tolerance of DNA polymerase gamma. Mutations in the POLG2 gene can lead to autosomal dominant progressive external ophthalmoplegia with mitochondrial DNA deletions. POLG2 is located on chromosome 17 and contains 8 exons. The protein encoded by this gene contains a phosphoserine modified residue, a transit peptide, and has a structure consisting of 25 beta strands, 21 alpha helixes, and 8 turns. POLG2 forms a heterotrimer with the catalytic subunit of DNA polymerase gamma, enhancing DNA binding, stimulating polymerase and exonuclease activity, and promoting processive DNA synthesis.

The POLG2 protein, also known as the accessory subunit of DNA polymerase gamma, plays a crucial role in mitochondrial DNA (mtDNA) replication. It acts as an allosteric regulator of the DNA polymerase gamma holoenzyme, enhancing its polymerase activity and processivity by strengthening its interaction with the DNA template. This protein also suppresses the exonucleolytic proofreading activity of DNA polymerase gamma, particularly towards homopolymeric templates with mismatched ends. Additionally, POLG2 binds to single-stranded DNA. These functions are supported by various studies, including those published in PubMed with IDs 11477093, 11477094, 11504725, 15167897, 19837034, 26056153, 30157269, 31778857, and 37202477.

POLG2 is also known as HP55, MTDPS16, MTDPS16A, MTDPS16B, MTPOLB, PEOA4, POLB, POLG-BETA, POLGB.

Associated Diseases

• Progressive external ophthalmoplegia with mitochondrial DNA deletions, autosomal dominant 4
• Mitochondrial DNA depletion syndrome 16 (hepatic type)
• Autosomal dominant progressive external ophthalmoplegia
• Mitochondrial DNA depletion syndrome 16B (neuroophthalmic type)