Journal: The Journal of Biological Chemistry
Article Title: Biochemical reconstitution of temozolomide-induced mutational processes
doi: 10.1016/j.jbc.2025.110676
Figure Lengend Snippet: Influence of TLS polymerases on the TMZ-induced mutation spectra in the presence and absence of hMGMT. A, illustration of the experimental system. dsDNA substrates were incubated with 400 μM TMZ three times. When indicated, damaged templates were treated with hMGMT. The DNA was heated and reannealed with NGS primer and 10x excess competitor to sequester the top strand. Then the primer extension was started by adding yPol δ. After 30 min of incubation with yPol δ, the second polymerase (either yPol ζ, hPol κ, or hPol η) was added, and the reaction was continued for another 30 min. B – D, mutation spectra produced on the TMZ-damaged DNA in the presence of the indicated second polymerase without hMGMT treatment. E–G, influences of the second polymerase on the C>T mutations were expressed as a ratio of the mutation frequencies at individual sites. CpC>T and CpT>T mutations (SBS11), other mutations (Others), and all mutations (All) are plotted as separate groups. H – J, the same experiments as in B – D were carried out using the templates that were treated with hMGMT. K, influences of hMGMT on the C>T and C>A mutations that were produced in the presence of indicated second polymerases. For hPol η reactions, only C>T mutations were analyzed because this polymerase did not produce considerable C>A mutations. Mutation frequencies mapped on the templates are shown in . hMGMT, human methylguanine methyltransferase; hPol κ, human Pol κ; hPol η, human Pol η; NGS, next-generation sequencing; SBS11, substitution signature 11; TLS, translesion synthesis; TMZ, temozolomide; yPol δ, yeast Pol δ.
Article Snippet: Human complementary DNA of MGMT (hMGMT) was obtained from SinoBiological , amplified by PCR, and cloned into pET21a to express MGMT with a C-terminal His6-tag.
Techniques: Mutagenesis, Incubation, Produced, Next-Generation Sequencing, Translesion Synthesis