Human polymorphic variants of the NEIL1 DNA glycosylase.
In mammalian cells, the repair of DNA bases that have been damaged by reactive oxygen species is primarily initiated by a series of DNA glycosylases that include OGG1, NTH1, NEIL1, and NEIL2. To explore the functional significance of NEIL1, we recently reported that neil1 knock-out and heterozygotic mice develop the majority of symptoms of metabolic syndrome (Vartanian, V., Lowell, B., Minko, I. G., Wood, T. G., Ceci, J. D., George, S., Ballinger, S. W., Corless, C. L., McCullough, A. K., and Lloyd, R. S. (2006) Proc. Natl. Acad. Sci. U. S. A. 103, 1864-1869). To determine whether this phenotype could be causally related to human disease susceptibility, we have characterized four polymorphic variants of human NEIL1. Although three of the variants (S82C, G83D, and D252N) retained near wild type levels of nicking activity on abasic (AP) site-containing DNA, G83D did not catalyze the wild type beta,delta-elimination reaction but primarily yielded the beta-elimination product. The AP nicking activity of the C136R variant was significantly reduced. Glycosylase nicking activities were measured on both thymine glycol-containing oligonucleotides and gamma-irradiated genomic DNA using gas chromatography/mass spectrometry. Two of the polymorphic variants (S82C and D252N) showed near wild type enzyme specificity and kinetics, whereas G83D was devoid of glycosylase activity. Although insufficient quantities of C136R could be obtained to carry out gas chromatography/mass spectrometry analyses, this variant was also devoid of the ability to incise thymine glycol-containing oligonucleotide, suggesting that it may also be glycosylase-deficient. Extrapolation of these data suggests that individuals who are heterozygous for these inactive variant neil1 alleles may be at increased risk for metabolic syndrome.
Roy
Laura M
LM
Center for Research on Occupational and Environmental Toxicology, Department of Molecular and Medical Genetics, Oregon Health and Science University, Portland, Oregon 97239-3098, USA.
Jaruga
Pawel
P
Wood
Thomas G
TG
McCullough
Amanda K
AK
Dizdaroglu
Miral
M
Lloyd
R Stephen
RS
D019943:Amino Acid Substitution; D000818:Animals; D045647:DNA Glycosylases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D004260:DNA Repair / Q000528:radiation effects; D043603:DNA-(Apurinic or Apyrimidinic Site) Lyase / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D043224:Deoxyribonuclease (Pyrimidine Dimer) / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D005720:Gamma Rays; D020022:Genetic Predisposition to Disease; D006801:Humans; D007700:Kinetics; D024821:Metabolic Syndrome / Q000201:enzymology / Q000235:genetics; D051379:Mice; D018345:Mice, Knockout; D020125:Mutation, Missense; D009838:Oligodeoxyribonucleotides / Q000737:chemistry; D011110:Polymorphism, Genetic
D009838:Oligodeoxyribonucleotides; D043224:Deoxyribonuclease (Pyrimidine Dimer); C468347:NTHL1 protein, human; D045647:DNA Glycosylases; C473634:NEIL1 protein, human; C481347:Neil1 protein, mouse; C479058:oxoguanine glycosylase 1, human; D043603:DNA-(Apurinic or Apyrimidinic Site) Lyase; C473642:NEIL2 protein, human