Misexpression of SoxE genes differentially rescues NC sublineage
specification and differentiation in
foxd3zdf10;tfap2aMO embryos. (A,E,H)
sox9a and sox9b (sox9a/b) RNA co-injection with
tfap2a morpholino (tfap2aMO) into
foxd3zdf10 mutant embryos
(foxd3zdf10-tfap2aMO). (A) Live 4 dpf
larva, dorsal view, anterior to the left. Melanophore and xanthophore
development is rescued in foxd3zdf10-tfap2aMO
embryos co-injected with sox9a/b RNA (arrows; compare with wild-type
embryo, D). (E) Alcian Blue staining of a 4 dpf larva, vental
views with anterior to the left. Misexpression of sox9a/b in
foxd3zdf10-tfap2aMO embryos results in rescue of
the neurocranium, as well as of the mandibular and hyoid jaw structures.
(H) dlx2 expression at 24 hpf, dorsal views, anterior to the
left. Specification of NC craniofacial progenitors occurs in
foxd3zdf10-tfap2aMO embryos co-injected with
sox9a/b RNA, based on dlx2 expression (arrows). (B,F,G,I,J)
foxd3zdf10-tfap2aMO embryos co-injected with
sox10 RNA. (B) Live 4 dpf larva, dorsal view, anterior to the
left. Consistent with a role in development of non-ectomesenchymal NC
derivatives, sox10 misexpression rescues melanophore and xanthophore
development in foxd3zdf10-tfap2aMO embryos
(arrows; compare with wild-type embryo, D). (F) Alcian Blue staining of
4 dpf larva, ventral view, anterior to the left. sox10 misexpression
does not rescue cranial cartilage structures in
foxd3zdf10-tfap2aMO embryos. (G) 16A11
immunoreactivity, 3 dpf, dorsal view. Dorsal root ganglion neuron development
is rescued by sox10 misexpression (arrowheads). (I)
dlx2 expression at 24 hpf, dorsal view with anterior to the left.
sox10 RNA injection also does not rescue NC dlx2 expression
in foxd3zdf10-tfap2aMO embryos (asterisks),
indicating that sox10 function cannot rescue the specification of NC
precursors for craniofacial cartilages. (J) th expression at
48 hpf, lateral view, anterior to the left. sox10 misexpression
rescues sympathetic neuron development (arrow). (C) Live 4 dpf larva,
dorsal view, anterior to the left. Morpholino-mediated knockdown of p53 in
foxd3zdf10-tfap2aMO embryos rescues melanophore,
xanthophore (arrows; compare with wild-type embryo, D) and iridophore (not
visible) development. (K-M) sox10-responsive NCCs persist in
foxd3zdf10-tfap2aMO embryos. 33 hpf embryos,
lateral view, anterior to left. (K) Wild-type embryo with abundant
melanophores. (L) In foxd3zdf10-tfap2aMO
embryos injected with a heat shock-inducible sox10 construct but not
exposed to heat shock, melanophores fail to develop. (M) In
foxd3zdf10-tfap2aMO embryos injected with a heat
shock-inducible sox10 construct and heat shocked at 24 hpf, robust
melanogenesis occurs.