title: Role of human DNA glycosylase Nei-like 2 (NEIL2) and single strand break repair protein polynucleotide kinase 3'-phosphatase in maintenance of mitochondrial genome.
abstract: 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.
authors: Department of Internal Medicine, University of Texas Medical Branch, Galveston, Texas 77555, USA.
authors: Santi M
authors: SM
authors: Mandal
authors: Muralidhar L
authors: ML
authors: Hegde
authors: Arpita
authors: A
authors: Chatterjee
authors: Pavana M
authors: PM
authors: Hegde
authors: Bartosz
authors: B
authors: Szczesny
authors: Dibyendu
authors: D
authors: Banerjee
authors: Istvan
authors: I
authors: Boldogh
authors: Rui
authors: R
authors: Gao
authors: Maria
authors: M
authors: Falkenberg
authors: Claes M
authors: CM
authors: Gustafsson
authors: Partha S
authors: PS
authors: Sarkar
authors: Tapas K
authors: TK
authors: Hazra
mesh_terms: D045304:Cytochromes c / Q000235:genetics / Q000378:metabolism; D053904:DNA Breaks, Single-Stranded; D045647:DNA Glycosylases / Q000235:genetics / Q000378:metabolism*; D000074002:DNA Polymerase gamma; D004260:DNA Repair / Q000502:physiology*; D045643:DNA Repair Enzymes / Q000235:genetics / Q000378:metabolism*; D043603:DNA-(Apurinic or Apyrimidinic Site) Lyase / Q000235:genetics / Q000378:metabolism*; D004259:DNA-Directed DNA Polymerase / Q000235:genetics / Q000378:metabolism; D054629:Genome, Mitochondrial / Q000502:physiology*; D057809:HEK293 Cells; D006801:Humans; D008928:Mitochondria / Q000201:enzymology* / Q000235:genetics; D024101:Mitochondrial Proteins / Q000235:genetics / Q000378:metabolism*; D017853:Phosphotransferases (Alcohol Group Acceptor) / Q000235:genetics / Q000378:metabolism*
chemical_list: D024101:Mitochondrial Proteins; D045304:Cytochromes c; C530380:PNKP protein, human; D017853:Phosphotransferases (Alcohol Group Acceptor); D000074002:DNA Polymerase gamma; D004259:DNA-Directed DNA Polymerase; D045647:DNA Glycosylases; D043603:DNA-(Apurinic or Apyrimidinic Site) Lyase; C473642:NEIL2 protein, human; D045643:DNA Repair Enzymes