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MutT homologue 1 (MTH1) catalyzes the hydrolysis of mutagenic O6-methyl-dGTP

Jemth, Ann-Sofie; Gustafsson, Robert; Bräutigam, Lars; Henriksson, Linda; Vallin, Karl S A; Sarno, Antonio; Almlöf, Ingrid; Homan, Evert; Rasti, Azita and Warpman Berglund, Ulrika, et al. (2018) In Nucleic Acids Research 46(20). p.10888-10904
Abstract

Nucleotides in the free pool are more susceptible to nonenzymatic methylation than those protected in the DNA double helix. Methylated nucleotides like O6-methyl-dGTP can be mutagenic and toxic if incorporated into DNA. Removal of methylated nucleotides from the nucleotide pool may therefore be important to maintain genome integrity. We show that MutT homologue 1 (MTH1) efficiently catalyzes the hydrolysis of O6-methyl-dGTP with a catalytic efficiency similar to that for 8-oxo-dGTP. O6-methyl-dGTP activity is exclusive to MTH1 among human NUDIX proteins and conserved through evolution but not found in bacterial MutT. We present a high resolution crystal structure of human and zebrafish MTH1 in complex with O6-methyl-dGMP. By... (More)

Nucleotides in the free pool are more susceptible to nonenzymatic methylation than those protected in the DNA double helix. Methylated nucleotides like O6-methyl-dGTP can be mutagenic and toxic if incorporated into DNA. Removal of methylated nucleotides from the nucleotide pool may therefore be important to maintain genome integrity. We show that MutT homologue 1 (MTH1) efficiently catalyzes the hydrolysis of O6-methyl-dGTP with a catalytic efficiency similar to that for 8-oxo-dGTP. O6-methyl-dGTP activity is exclusive to MTH1 among human NUDIX proteins and conserved through evolution but not found in bacterial MutT. We present a high resolution crystal structure of human and zebrafish MTH1 in complex with O6-methyl-dGMP. By microinjecting fertilized zebrafish eggs with O6-methyl-dGTP and inhibiting MTH1 we demonstrate that survival is dependent on active MTH1 in vivo. O6-methyl-dG levels are higher in DNA extracted from zebrafish embryos microinjected with O6-methyl-dGTP and inhibition of O6-methylguanine-DNA methyl transferase (MGMT) increases the toxicity of O6-methyl-dGTP demonstrating that O6-methyl-dGTP is incorporated into DNA. MTH1 deficiency sensitizes human cells to the alkylating agent Temozolomide, a sensitization that is more pronounced upon MGMT inhibition. These results expand the cellular MTH1 function and suggests MTH1 also is important for removal of methylated nucleotides from the nucleotide pool.

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Nucleic Acids Research
volume
46
issue
20
pages
10888 - 10904
publisher
Oxford University Press
external identifiers
  • scopus:85056590509
ISSN
1362-4962
DOI
10.1093/nar/gky896
language
English
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no
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189331b0-8f8f-472d-b683-7bf7835794c8
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2019-04-30 07:44:32
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2019-09-17 04:52:14
@article{189331b0-8f8f-472d-b683-7bf7835794c8,
  abstract     = {<p>Nucleotides in the free pool are more susceptible to nonenzymatic methylation than those protected in the DNA double helix. Methylated nucleotides like O6-methyl-dGTP can be mutagenic and toxic if incorporated into DNA. Removal of methylated nucleotides from the nucleotide pool may therefore be important to maintain genome integrity. We show that MutT homologue 1 (MTH1) efficiently catalyzes the hydrolysis of O6-methyl-dGTP with a catalytic efficiency similar to that for 8-oxo-dGTP. O6-methyl-dGTP activity is exclusive to MTH1 among human NUDIX proteins and conserved through evolution but not found in bacterial MutT. We present a high resolution crystal structure of human and zebrafish MTH1 in complex with O6-methyl-dGMP. By microinjecting fertilized zebrafish eggs with O6-methyl-dGTP and inhibiting MTH1 we demonstrate that survival is dependent on active MTH1 in vivo. O6-methyl-dG levels are higher in DNA extracted from zebrafish embryos microinjected with O6-methyl-dGTP and inhibition of O6-methylguanine-DNA methyl transferase (MGMT) increases the toxicity of O6-methyl-dGTP demonstrating that O6-methyl-dGTP is incorporated into DNA. MTH1 deficiency sensitizes human cells to the alkylating agent Temozolomide, a sensitization that is more pronounced upon MGMT inhibition. These results expand the cellular MTH1 function and suggests MTH1 also is important for removal of methylated nucleotides from the nucleotide pool.</p>},
  author       = {Jemth, Ann-Sofie and Gustafsson, Robert and Bräutigam, Lars and Henriksson, Linda and Vallin, Karl S A and Sarno, Antonio and Almlöf, Ingrid and Homan, Evert and Rasti, Azita and Warpman Berglund, Ulrika and Stenmark, Pål and Helleday, Thomas},
  issn         = {1362-4962},
  language     = {eng},
  month        = {11},
  number       = {20},
  pages        = {10888--10904},
  publisher    = {Oxford University Press},
  series       = {Nucleic Acids Research},
  title        = {MutT homologue 1 (MTH1) catalyzes the hydrolysis of mutagenic O6-methyl-dGTP},
  url          = {http://dx.doi.org/10.1093/nar/gky896},
  volume       = {46},
  year         = {2018},
}