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

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.

Gustafsson, RobertStockholms universitet,Institutionen för biokemi och biofysik (författare)
Brautigam, LarsKarolinska Institutet (författare)
Henriksson, LindaStockholms universitet,Institutionen för biokemi och biofysik(Swepub:su)lisv7249 (författare)
Vallin, Karl S. A. (författare)
Sarno, Antonio (författare)
Almlof, IngridKarolinska Institutet (författare)
Homan, EvertKarolinska Institutet (författare)
Rasti, Azita (författare)
Berglund, Ulrika WarpmanKarolinska Institutet (författare)
Stenmark, PålStockholms universitet,Institutionen för biokemi och biofysik(Swepub:su)stenm (författare)
Helleday, ThomasKarolinska Institutet (författare)
Karolinska InstitutetInstitutionen för biokemi och biofysik (creator_code:org_t)

Ingår i:Nucleic Acids Research: Oxford University Press (OUP)46:20, s. 10888-109040305-10481362-4962

Av författaren/redakt...: Jemth, Ann-Sofie; Gustafsson, Robe ...; Brautigam, Lars; Henriksson, Lind ...; Vallin, Karl S. ...; Sarno, Antonio; visa fler...; Almlof, Ingrid; Homan, Evert; Rasti, Azita; Berglund, Ulrika ...; Stenmark, Pål; Helleday, Thomas; visa färre...

Om ämnet

Kungliga biblioteket hanterar dina personuppgifter i enlighet med EU:s dataskyddsförordning (2018), GDPR. Läs mer om hur det funkar här.
Så här hanterar KB dina uppgifter vid användning av denna tjänst.