Fig. 2

Cellular proliferation rates in HAP1 and ΔSHMT2 cells. Formate rescues cell proliferation rate in HAP1 cells cultured in low-folate medium but not in ΔSHMT2 cells. Cell proliferation rates of ΔSHMT2 cells were compared with HAP1 cells by co-staining cells with Hoechst 33342 (to identify all cells) and propidium iodide (to identify dead cells). Fold change of each group was calculated by dividing by day 0 cell number. Data represent means ± SD values. Values represent n = 6 replicates of cell lines cultured in medium containing either 25 nM (6S)5-formyl-THF or 0 nM (6S)5-formyl-THF. A Cell proliferation rate and cell proliferation rate in the presence of 2 mM formate, B relative days 1–4 quantitation of cell proliferation rate, and C relative days 1–4 quantitation cell proliferation rate in the presence of 2-mM formate. Linear mixed-effects models with main effects of media, genotype, and time (with time as a continuous variable) and 2- and 3-way interactions were used to determine cell proliferation with a statistical significance at p < 0.05. Two-way ANOVA with Tukey’s post hoc analysis was used to determine media by genotype interaction and main effects of media, and genotype with a statistical significance at p < 0.05 were used to analyze individual day proliferation. Levels not connected by the same letter are significantly different