Fig. 2

Dynamic changes of DNA methylation in the SPDEF promoter during goblet cell differentiation of PBEC from control subjects. a Schematic representation of the promoter region of the SPDEF gene, outlining the putative binding sites for the most relevant transcription factors (STAT6, GFI, NKX2-1/NKX3-1, SMAD, and FOXA1/FOXA2) as analyzed using MatInspector software. The transcription start site was shown as +1. CpGs are indicated as vertical bars. DNA methylation status of 15 CpGs was analyzed using pyrosequencing for the indicated areas. b PBEC from control subjects1–6 (Table 1, n = 6) were cultured at ALI, and DNA methylation levels were analyzed at four different time points. Data represent the connected median methylation levels (min to max) of different CpG sites at each time points, and differential methylated CpG sites are specified with medians indicated. Significance was tested by the Kruskal-Wallis non-parametric test with Dunn’s posttest data. ns not significant. *p < 0.05; **p < 0.01. Data from days 14, 21, and 28 were compared to day 0