MUTYH prevents OGG1 or APEX1 from inappropriately processing its substrate or reaction product with its C-terminal domain.
MutY homolog (MUTYH) excises adenine opposite 8-oxoguanine (8-oxoG) in DNA, thus preventing occurrence of G:C to T:A transversion. In cell-free extract prepared from the thymocytes of wild type but not MUTYH-null mice, adenine opposite 8-oxoG in DNA was excised by MUTYH, however, the generated apurinic (AP) site opposite 8-oxoG mostly remained unincised. Recombinant mouse MUTYH (mMUTYH) efficiently excised adenine opposite 8-oxoG and prevented mouse AP endonuclease (mAPEX1) from incising the generated AP site. In contrast, an AP site opposite 8-oxoG created by uracil DNA glycosylase or tetrahydrofuran opposite 8-oxoG was efficiently incised by mAPEX1 in the presence of an excess amount of mMUTYH. Mutant mMUTYH with R361A or G365D substitution, excised adenine opposite 8-oxoG as efficiently as did wild-type mMUTYH, but failed to prevent mAPEX1 from incising the generated AP site. Wild-type mMUTYH bound duplex oligonucleotides containing A:8-oxoG pair with a lower apparent K(d) than that of the mutants, and prevented OGG1 from excising 8-oxoG opposite adenine or the generated AP site. The G365D mutant failed to prevent OGG1 from excising 8-oxoG opposite the generated AP site, thus indicating that the protection of its own product by mMUTYH is an intrinsic function which depends on the C-terminal domain of mMUTYH.
Tominaga
Yohei
Y
Division of Neurofunctional Genomics, Department of Immunobiology and Neuroscience, Medical Institute of Bioregulation, Kyushu University, Fukuoka 812-8582, Japan.
Ushijima
Yasuhiro
Y
Tsuchimoto
Daisuke
D
Mishima
Masaki
M
Shirakawa
Masahiro
M
Hirano
Seiki
S
Sakumi
Kunihiko
K
Nakabeppu
Yusaku
Y
D000225:Adenine / Q000378:metabolism; D000595:Amino Acid Sequence; D019943:Amino Acid Substitution; D000818:Animals; D045647:DNA Glycosylases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D043603:DNA-(Apurinic or Apyrimidinic Site) Lyase / Q000378:metabolism*; D006151:Guanosine / Q000031:analogs & derivatives* / Q000378:metabolism; D051379:Mice; D008969:Molecular Sequence Data; D017434:Protein Structure, Tertiary; D011994:Recombinant Proteins / Q000378:metabolism
D011994:Recombinant Proteins; D006151:Guanosine; C046215:8-hydroxyguanosine; D045647:DNA Glycosylases; C061738:mutY adenine glycosylase; C479058:oxoguanine glycosylase 1, human; C486216:Apex1 protein, mouse; D043603:DNA-(Apurinic or Apyrimidinic Site) Lyase; D000225:Adenine