Correlation between FXYD3 expression and percent of methylation of individual CpGs.

DNA from control (n = 8) and T2D (n = 8) human islets were extracted from the same samples as used for the real-time PCR analysis. Then, the 32 CpGs of the FXYD3 promoter from −1 to −1200 were analyzed by pyrosequencing. Correlation analysis between methylation level and FXYD3 expression measured by quantitative RT-PCR was performed for each CpG using the non-parametric Pearson test. 7 CpG sites in the proximal FXYD3 promoter showed significant correlation between methylation level and FXYD3 expression. Within these 7 CpGs, 2 sites showed strongly significant correlation between methylation and FXYD3 mRNA expression only in the T2D group.