Mutations induced by 2-hydroxy-dATP during in vitro replication with a HeLa extract.

The mutagenicity of oxidized dATP, 2-hydroxydeoxyadenosine 5'-triphosphate (2-OH-dATP), was examined using an SV40 origin-dependent in vitro replication system with a HeLa extract. 2-OH-dATP mainly elicited a G x C to A x T transition, and a G x C to T x A transversion to a lesser extent. Interestingly, the mutagenicity of 2-OH-dATP was enhanced in the presence of 2-hydroxydeoxyadenosine 5'-diphosphate, an inhibitor of the MTH1 protein, suggesting that this protein functions in the hydrolysis of 2-OH-dATP in the replication reaction mixture. These results indicate that 2-OH-dATP is mutagenic and that its mutagenicity is suppressed by the MTH1 protein in mammalian cells.