Fig. 5.

Effect of MSH2 deletion on the DNA content of T. brucei before and after hydrogen peroxide exposure. (A) Quantitation of the nuclear (N) and kinetoplast (K) DNA content of T. brucei wild type and ΔTcmsh2::BSD/Tcmsh2::PUR mutants after 72 h growth in the presence or absence of increasing concentrations of H₂O_2. DNA in the cells was visualized by DAPI staining; >500 cells were counted in each sample. Only aberrant cells that differ from the expected N/K ratios (1N1K, 1N2K or 2N2K) are shown, as a percentage of the total population. (B, C) Examples of ΔTcmsh2::BSD/Tcmsh2::PUR cells lacking detectable kDNA are shown after 72 h growth in 100 μM H₂O₂ (B) or without H₂O₂ treatment (C); in all cases the cells are shown both as a DAPI-stain image or as a merge of DAPI and differential interference contrast images and arrows denote the cells lacking kDNA, which are shown beside 1N1K cells for comparison.