Investigation into the promoter DNA methylation of three genes (CAMK1D, CRY2 and CALM2) in the peripheral blood of patients with type 2 diabetes

Abstract

Promoter DNA methylation may reflect the interaction between genetic backgrounds and environmental factors in the development of metabolic disorders, including type 2 diabetes (T2D). Calcium/calmodulin-dependent protein kinase 1D (CAMK1D), cryptochrome 2 (CRY2) and calmodulin 2 (CALM2) genes have been identified to be associated with a risk of T2D. Therefore, the aim of the present study was to investigate the contribution of promoter DNA methylation of these genes to the risk of T2D. Using bisulfite pyrosequencing technology, the DNA methylation levels of the CpG dinucleotides within the CAMK1D, CRY2 and CALM2 gene promoters were measured in 48 patients with T2D and 48 age- and gender-matched healthy controls. The results demonstrated that the promoters of these three genes were hypomethylated in the peripheral blood of all the subjects, and DNA methylation of these three genes did not contribute to the risk of T2D.

Keywords: DNA methylation; calcium/calmodulin-dependent protein kinase 1D; calmodulin 2; cryptochrome 2; promoter; type 2 diabetes.

Figure 1

CpG islands within the CAMK1D, CRY2 and CALM2 promoters. The diagrams indicate the correlation coefficients, and (A) nine CpG dinucleotides within CAMK1D, (B) four CpG dinucleotides within CALM2 and (C) five CpG dinucleotides within CRY2. ^*P<0.05, ^**P<0.01. P-values were calculated by Pearson test which analyzed the correlation of the methylation levels among the tested CpGs. CALM2, calmodulin 2; CRY2, cryptochrome 2; CAMK1D, calcium/calmodulin-dependent protein kinase 1D.

Figure 2

DNA methylation of all the CpGs within the CAMK1D, CRY2 and CALM2 promoters. Methylation levels of each dinucleotide of the (A) four CpGs within CALM2, (B) five CpGs within CRY2 and (C) nine CpGs within CAMK1D. CALM2, calmodulin 2; CRY2, Cryptochrome 2; CAMK1D, calcium/calmodulin-dependent protein kinase 1D.