Mef2ca and Mef2cb dual loss of function abolishes myocardial differentiation. A,B. In situ mRNA hybridisation for myl7 in hearts of 24 hpf mef2cab1086;mef2cbfh288 mutant embryos and their siblings (A) or control and mef2cb+/fh288 incross embryos non-injected or injected with mef2ca MO, shown in a dorsal view, anterior to top. Double mutants have almost no myl7 expression albeit few cells in the cardiac region (arrows, A). Mef2cbfh288 mutant embryos injected with mef2ca MO have a thinner than normal heart tube. All other control or embryos with only one Mef2 depleted have a normal heart. C. Bright field images of mef2cbfh288 mutant embryos injected with mef2ca MO showing cardiac edema, compared with mef2ca MO injected siblings with normal heart and no edema. Scale = 100 μm.
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