Role of human DNA glycosylase Nei-like 2 (NEIL2) and single strand break repair protein polynucleotide kinase 3'-phosphatase in maintenance of mitochondrial genome.

• The repair of reactive oxygen species-induced base lesions and single strand breaks (SSBs) in the nuclear genome via the base excision (BER) and SSB repair (SSBR) pathways, respectively, is well characterize, and important for maintaining genomic integrity. However, the role of mitochondrial (mt) BER and SSBR proteins in mt genome maintenance is not completely clear. Here we show the presence of the oxidized base-specific DNA glycosylase Nei-like 2 (NEIL2) and the DNA end-processing enzyme polynucleotide kinase 3'-phosphatase (PNKP) in purified human mitochondrial extracts (MEs). Confocal microscopy revealed co-localization of PNKP and NEIL2 with the mitochondrion-specific protein cytochrome c oxidase subunit 2 (MT-CO2). Further, chromatin immunoprecipitation analysis showed association of NEIL2 and PNKP with the mitochondrial genes MT-CO2 and MT-CO3 (cytochrome c oxidase subunit 3); importantly, both enzymes also associated with the mitochondrion-specific DNA polymerase γ. In cell association of NEIL2 and PNKP with polymerase γ was further confirmed by proximity ligation assays. PNKP-depleted ME showed a significant decrease in both BER and SSBR activities, and PNKP was found to be the major 3'-phosphatase in human ME. Furthermore, individual depletion of NEIL2 and PNKP in human HEK293 cells caused increased levels of oxidized bases and SSBs in the mt genome, respectively. Taken together, these studies demonstrate the critical role of NEIL2 and PNKP in maintenance of the mammalian mitochondrial genome.

Ämnesord

MEDICIN OCH HÄLSOVETENSKAP  -- Medicinska och farmaceutiska grundvetenskaper (hsv//swe)

MEDICAL AND HEALTH SCIENCES  -- Basic Medicine (hsv//eng)

Nyckelord

Cytochromes c

genetics

metabolism

DNA Breaks

Single-Stranded

DNA Glycosylases

genetics

metabolism

DNA Repair

physiology

DNA Repair Enzymes

genetics

metabolism

DNA-(Apurinic or Apyrimidinic Site) Lyase

genetics

metabolism

DNA-Directed DNA Polymerase

genetics

metabolism

Genome

Mitochondrial

physiology

HEK293 Cells

Humans

Mitochondria

enzymology

genetics

Mitochondrial Proteins

genetics

metabolism

Phosphotransferases (Alcohol Group Acceptor)

genetics

metabolism

Publikations- och innehållstyp

ref (ämneskategori)

art (ämneskategori)