Figure legends
FIGURE 1: HLA-DRB1 and HLA-G genes’ chromosomal
location, transcripts (dark blue), protein domains (light blue) and CpG
islands (green boxes) from GENCODE v.38 (exons are presented as boxes
and introns as lines, arrows indicate the 5’-3’ direction). Analyzed
genomic areas with CpGs are displayed as purple arrows. Different colors
correlate with transcription factors’ binding sites, potentially
affected from methylation status of studied CpGs. SNPs and their
location across the analyzed regions are displayed as red arrows.
rs17878951 is involved in the creation of a new CpG site, while
rs75044270 is involved in the deletion of a CpG site withinHLA-DRB1 region. Sequencing primers of each genetic region are
also presented.
FIGURE 2: Methylation levels of FOXP3 TSDR and HLA-G
promoter. (A) Methylation pattern of reverse (R5) and forward (F5) DNA
strand of FOXP3 TSDR among control and FA sample group.
Differential methylation profiles were observed between the two DNA
strands. (B, C) Methylation status of specific CpG sites lying withinFOXP3 TSDR and HLA-G promoter and total values from all
CpGs studied across each region. HLA-G promoter’s CpG site 2
showed statistically significant differences between control and food
allergy group (**p=0.004). (D) Effect of
rs1233333 on DNA methylation
levels of HLA-G promoter region. Homozygous genotype AA showed
decreased methylation compared to homozygous GG. Data are presented as
mean ± SE. CpG sites across studied region are numbered relative to
5’-3’ direction.
* Indicates p value <0.05, **indicates p value <
0.01
FIGURE 3 : DNA methylation levels of food allergic children and
non-allergic controls with and without parental smoking history. (A)
Parental smoking habit significantly influenced methylation levels of
CpG site 1 (p=0.004), CpG site 5 (p=0.004), CpG site 6 (p=0.011) και CpG
site 9 (p=0.023) of FOXP3 TSDR regardless of FA or healthy
status. (B) Parental smoking habit in combination with FA significantly
influenced methylation levels of specific CpG sites in HLA-Gpromoter: CpG site 3 (p<0.001), CpG site 4 (p=0.028), CpG site
5 (p=0.009), CpG site 6 (p=0.002), CpG site 7 (p=0.036) and whole tested
genetic region (p=0.004).
FIGURE 4 : Methylation levels of a 70bp highly polymorphic
region within CpG41 of HLA-DRB1 gene. Absence of SNPs is
accompanied with complete demethylation (<5%), while the
presence of SNPs causes simultaneous high methylation levels
(>70%). Data are presented as mean ± SE.