Summary of the correlations between the expression of Methyl CpG binding protein 2 gene ( Mecp2 ) isoforms and DNA methylation at the Mecp2 regulatory elements. (A) Dynamic changes in the expression of Mecp2 isoforms (Mecp2e1 and Mecp2e2) at different time points of neural stem cell (NSC) differentiation at day 0 (D0), D2 and D8. Decitabine caused upregulation of Mecp2e1/MeCP2E1 but not Mecp2e2 at D2. Decitabine effect on MeCP2E2 at the protein levels is unknown. Decitabine withdrawal by D8 downregulated Mecp2e1/MeCP2E1, and Mecp2e2/ MeCP2E2 (unknown) to different extents. (B) Schematic representation of the correlation between Mecp2 isoform-specific expression and DNA methylation at the Mecp2 promoter regions (R1 to R3), and intron 1 regions (R4 to R6). The size of the signs, plus (+), and minus (-) represents the relative degree of correlation with either Mecp2 isoform. The statistically significant correlations are represented in red (red-circled plus, red-circled minus). After decitabine exposure Mecp2e1 expression negatively correlated with promoter R1 and R3, and intron 1 R5. Mecp2e2 isoform negatively correlates with promoter R3. In contrast, after decitabine withdrawal, Mecp2e1 expression negatively correlated with promoter R1, R2 and R3, and positively correlated with intron 1 R6. Hence, correlation between Mecp2e1 and DNA methylation at REs changed depending on the stage of NSC differentiation. Mecp2e2 isoform positively correlated with intron 1 R4 and R6.