Fig. 7

The methylation levels of the three imprinted loci are consistently modified following exposure to cigarette smoking. The left, center, and right panels are respectively centered on the DMRs associated with the NNAT locus ± 2 kb, the SGCE/PEG10 locus ± 2 kb, and the H19/MIR675 locus ± 2 kb. The top panels show the heatmaps corresponding to H3K4me3, H3K4me1, and H3k27ac enrichments in the placenta around the center of the region of interest ± 2 kb. For each mark, we downloaded triplicates from ENCODE data (see the “Methods” section). We computed the enrichment matrices from bigWig files using the deepTools software and displayed it using a custom R script. The middle panels show genes and CpG islands from the Illumina Infinium Human Methylation 450K BeadChip annotations, ICR from Pervjakova et al. [54], the DMR we identified, and the corresponding Illumina probes of the region of interest. The lower panels show the methylation changes in smokers (S) in red (resp. former smokers (FS) in blue) compared to non-smokers. The points represent the beta of the linear model, and the error bars correspond to 2 standard deviations. The Y-axis represents the distributions of the variations of the regression coefficient (i.e., the associated change in DNA methylation level between 0 and 1) for each CpG within the DMRs selected by our analysis