Abstract: Objective To study the DNA methylation of E-boxes which may or may not be involved in the protein/DNA interacting and in the MKP1 tissue-specific expressions. To study the DNA methylation of E-boxes which may or not involved in the protein/DNA interacting and in the MKP1 tissue-specific expressions. Methods C57 BL/6J male mice were randomized into 6 groups and were sacrificed at six different time points during a 24-hour period. Liver and kidney were isolated. Genomic DNA was extracted and DNA methylation was examined using bisulfite sequencing analysis. Results All E-boxes and their surrounding CpG islands were free from methylation. The methylation status of the E-box in the MKP1 promoter in different tissues was also negative. Conclusion Our results indicated that DNA methylation does not determine distinct binding features of circadian genes and also does not regulate the tissue specific clock control of MKP1.

Key words: clock gene, E-box, CpG island, DNA methylation