Defects in the formation of pharyngeal arches in irxl1 morphants. A-S: Whole-mount in situ hybridization of nkx2.3 expression at 30 (A,B) and 48 (C,D) hours postfertilization (hpf), myoD expression at 48 (E,F), and 58 (G,H) hpf, dlx2 expression at 30 hpf (I-L), sox9a expression at 48 hpf (M-P), and runx2b expression at 48 hpf (Q-S). Both MOI (plus p53 MO) and MOII morphants are analyzed and shown as indicated. A-D,K-L,O-S: Dorsal views. E-J,M-N: Lateral views. B,D: The endodermal pouches form at 30 hpf (B) but are disorganized at 48 hpf (D). F,H: The pharyngeal arch muscle and some extraocular muscle precursors are missing in morphants (arrows). J,L: The expression domains of dlx2 are reduced in morphants, especially in the branchial arches (arrows). N,P,R,S: Note that expression domains of sox9a in the ceratobranchials (arrows in N,P) and runx2b in ceratobranchials 3-4 (arrows in R,S) and the parasphenoid (asterisks in R,S) are severely reduced in morphants. b, branchial arches; cb, ceratobranchials; ch, ceratohyal; cl, cleithrum; di, diencephalon; em, extraocular muscles; ep, endodermal pouches; h, hyoid arch; m, mandibular arch; MO, morpholino oligonucleotides; ms, Meckel′s; pam, pharyngeal arch muscles; pq; palatoquadrate; ps, parasphenoid; te, telencephalon. Scale bars = 100 μm in A-P,Q-S.
|
