Fig. 8.

Over-expression of CamkIIδ with or without RA in C2C12 cells. a–c Over-expression of CamkIIδin proliferating C2C12 cells. Q-PCR showed that CamkIIδ expression was up-regulated obviously in C2C12 myoblasts transfected with CamkIIδ than in cells transfected with control plasmid. On the contrary, the expression of miR-31-5p was not influenced by the transfection of CamkIIδ (a). Immunofluorescence of BrdU labeling of C2C12 myoblasts transfected with control plasmid, C2C12 myoblasts with excessRA and control plasmid, C2C12 myoblasts transfected by CaMKIIδ, and C2C12 myoblaststransfected by CaMKIIδwith RA (b). The statistical analysis of BrdU positive cells of proliferating C2C12 cells indicated that transfection of CamkIIδimproved the proliferation of C2C12 cells and could overcome the effects of RA on C2C12 proliferation, compared with the C2C12 transfected only by control plasmid and supplemented withRA (c). d–f Over-expression of CamkIIδin differentiating C2C12 cells. Q-PCR indicated that the expression of CamkIIδ in differentiating C2C12 cells was increased with or without RA (d). Immunofluorescence of myosin staining of C2C12 myoblasts transfected with control plasmid, C2C12 myoblasts supplemented with RA and control plasmid, C2C12 myoblasts transfected by CamkIIδ without RA, and C2C12 myoblasts transfected by CamkIIδwith RA (e). The statistics of fusion index of all differentiating C2C12 groups showed that the differentiation of the C2C12 cells transfected by CamkIIδ and with excess RA was significantly improved compared with the C2C12 only supplemented with RA, it was still much lower than the control group and the C2C12 transfected only CamkIIδ (f). (*P < 0.05 and **P < 0.01)