Transcriptional activity of MyoD and MEF2 is
activated by the CaMK- and calcineurin-mediated signaling pathways. (A
and B) C2C12 cells were transfected with either 3MEF2-luc (A) or
4RE-luc (B) in combination with either an empty vector, the
constitutively active CaMKIVc, or CnAΔ. (C) 10T1/2 cells stably
expressing MyoD were transfected with 4RE-luc along with various
plasmids as indicated. (D) HeLa cells were transfected with gal4-luc,
gal4MyoD along with either an empty expression vector or various active
signaling molecules as indicated. (E) C2C12 cells were transfected with
3MEF3-luc in combination with vectors encoding signaling molecules as
indicated. WCE were made for luciferase activity determination either
24 h (for assays in A, B, D, and E) or 48 h (for assays in C)
after cells were grown in DM. All of the above-mentioned experiments
were repeated three times, and a representative is shown. The numbers
on top of each bar indicate the fold activation.