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FIG. 6. Inhibition of cranial nerve development by NF-MDT. Embryos were injected unilaterally with either NF-MDT mRNA (A)or b-galactosidase mRNA (E, F) at the 2-cell stage and then immunostained with the anti-MAP1 antibody as wholemounts at stage 28 (A and B) or stage 37/38 (C ). (A, C, and E) The side of the animal derived from the injected blastomere. (B, D, and F) The respective contralateral uninjected side of the same animals. At stage 28, Vop (A, labeled arrowhead) developed to a lesser extent than on the contralateral, uninjected side (B). The unlabeled arrowheads in B show additional segments of Vop that are missing from the injected side. At stage 37/38 (C), cranial nerve development was more dramatically inhibited. (C) Inhibition of cranial nerves Vop, Vmd, VII, IX, and X. (D) Normal development of these same nerves on the contralateral side. Xb, Xv , and Xl are especially well developed on this side compared to the injected side. (E and F) Cranial nerve development was unaffected by expression of b-galactosidase. Cranial nerves on both sides of the head developed symmetrically, and the extent of nerve development was similar to that in D. (The dorsal side of the animals shown in E and F is rotated slightly forward.) Abbreviations: E, eye; O, otic vesicle; Vop , ophthalmic branch of the trigeminal nerve; Vmd, mandibular branch of the trigeminal nerve; VII, branch of the facial nerve; IX, branch of the glossopharyngeal nerve; Xb , brachial branch of the Xth cranial nerve; Xv visceral branch of Xth cranial nerve; Xl lateral line branch of the Xth cranial nerve. The scale bar applies to all panels. |
