Figure 3.

Inhibition of SRF expression by SRF antisense does not inhibit Myf5 expression while blocking efficiently MyoD expression. Control C2 cells (stably transfected with the glucocorticoid receptor only) and SRF antisense C2 cells (stably transfected with the glucocorticoid receptor and dexamethasone-inducible antisense SRF) (see Soulez et al., 1996) were cultured in proliferation medium for 3 d in the presence or absence of 10⁻⁶ M dexamethasone to induce the production of SRF antisense. (A) cells were fixed and stained for MyoD (a and e) or Myf5 (c and g) and for DNA with Hoechst dye (b, d, f, and h) after 3 d of culture in the absence (a, b, c, and d) or presence (e, f, g, and h) of 10⁻⁶ M dexamethasone (Dexa). (B) Culture conditions are the same as the one described above. Three days after plating, proteins were extracted and immunoblot analyses were performed with rabbit anti-MyoD antibodies, rabbit anti-Myf5 antibodies, and rabbit anti-annexin antibodies as described in MATERIALS AND METHODS.