Fig. 5

Calcitriol activates the promoter of Mbnl1 in myogenic cells. (a) Schematic diagram showing the position of promoter of Mbnl1 gene (pMbnl1). Exons are shown by boxes, introns by thin lines, and pMbnl1 by a black closed square. (b) Schematic diagram of pGL3E vector and pMbnl1-pGL3E vector. In pMbnl1-pGL3E, the pMbnl1 region was cloned into pGL3E upstream of the firefly luciferase gene. (c) Luciferase activity of pGL3E or pMbnl1-pGL3E during myogenic differentiation of C2C12 myoblasts. Cells were treated with different concentrations of calcitriol from differentiation day 0, whole cell lysates were extracted and firefly luciferase activity was evaluated on day 5 after induction of differentiation. Firefly luciferase activity was normalized to the Renilla luciferase activity of co-transfected pRL-CMV, and also to 0 nM treated cells. Mean and SD (n = 5 culture dishes) are indicated. ***p < 0.001, and n.s., not significant by one-way ANOVA followed by Turkey multiple comparison correction