Fig. 1
Endogenous and MMS-induced base methylations in total- and mRNA in HeLa cells. A Mass chromatograms of methylated bases in total RNA isolated from non-treated (upper panels) or MMS-treated (lower panels) HeLa cells after 1Â h exposure of 1Â mM MMS. Red graphs represent fraction of the bases containing light (CH3) methyl and blue graphs represent fraction containing deuterated (CD3) methyl in each modified nucleoside. Increased CH3/CD3 ratios after MMS treatment are mediated by non-enzymatic, MMS-mediated methylation (CH3). B Similar as in A, but with mRNA. C Concentrations of MMS-induced methyl adducts in total- and mRNA. D Relative distribution of MMS-induced methyl adducts in total- and mRNA. E Endogenous levels of methylated bases in total- and mRNA in untreated cells. F Total number of various base methylations in total- and mRNA with the relative amounts of endogenous and MMS-induced base methylations as indicated by differential coloring. Each bar in C-F represents the mean of three biological replicates with SDs as indicated