Myf5 is required for cranial muscle development, except the primordia of mr/ir/sr. Embryos derived from the transgenic line Tg(α-actin:RFP; A, B) and from the wild-type strain (C–J) were used. All the embryos were lateral views except panels E and F, which were dorsal–lateral view. The embryos injected with 4 ng of myf5-morpholino oligonucleotide (MO) to inhibit myf5 translation specifically, were studied to observe the development of cranial muscle (B) and the expression of myod, et1, and myogenin (D, F, H, J) at the stages indicated. Red fluorescent protein (RFP) signal was detected only in the mr/ir and sr primordia in the myf5 transgenic morphant (A vs. B). myod was expressed only in the mr/ir/sr primordia in the myf5 wild-type morphant at 36 hpf (C vs. D) and at 58 hpf (G vs. H). Similarly, myogenin was detected only in the mr/ir/sr primordia in myf5 morphant (I vs. J). However, the et1 transcript was changed little in the ventral arch mesoderm core in the myf5 morphant (E vs. F, arrows), indicating that the development of the ventral arch mesoderm core in myf5 morphant was normal.
|
