Next, we investigated Mecp2 isoform-specific transcript expression at three stages of NSC differentiation: undifferentiated cells (D0), cells at an early stage of differentiation (D2), and cells at a later stage of differentiation (D8). Distinct and mirror-like (reciprocal) transcript expression patterns for Mecp2 isoforms were observed during NSC differentiation (D0, D2, and D8) (Figure 3A), suggesting possible differential regulation of these isoforms during NSC differentiation. Expression of Mecp2e1 was reduced from D0 to D2 (2.7-fold, P <0.001) and was slightly elevated from D2 to D8. In contrast, Mecp2e2 expression increased from D0 to D2 (3.1-fold, P <0.05), but declined from D2 to D8 (4.2-fold, P <0.01). At each of these studied differentiation stages, the expression ratio between the two isoforms (Mecp2e1/Mecp2e2) varied significantly (D0, 5.99; D2, 0.69; D8, 4.62) (Additional file 3). At D0 and D8, Mecp2e1 expression was significantly higher than Mecp2e2 (D0, P <0.01, and D8, P <0.05). In contrast at D2, Mecp2e2 expression was significantly higher than Mecp2e1 (D2, P <0.05). These observations imply differential regulation of Mecp2 isoforms and possible changes in alternative splicing of Mecp2 at different stages of NSC differentiation.
