Distinct effects of Bmp4 and Edn1 misexpression on hand2 and dlx3b/5a expression. (A-J) Confocal sections of in situ hybridization for hand2 (green) with dlx3b (red, A-E) or dlx5a (red, F-J) in the mandibular (1) and hyoid (2) arches of 36 hpf control hsp70I:Gal4 (A,F) and hsp70I:Gal4; UAS:Bmp4 embryos subjected to a 20-24 hpf heat-shock (B,G), as well as hsp70I:Gal4; UAS:Edn1 embryos subjected to a 20-28 hpf heat-shock (C,H). (A,F) In controls, hand2 (n=48/48) was restricted to the ventral domain, and dlx3b (n=30/30) and dlx5a (n=18/18) to intermediate domains. (B,G) In UAS:Bmp4 embryos, hand2 was upregulated (n=23/32), dlx3b was variably expanded (n=11/21) or reduced (n=9/21), and dlx5a was also variably expanded (n=4/20) or reduced (n=9/20). (C,H) In UAS:Edn1 embryos, hand2 was reduced (n=34/34) and dlx3b (n=20/20) and dlx5a (n=14/14) were expanded. (D,E,I,J) Un-injected hsp70I:Gal4; UAS:Bmp4 embryos subjected to a 3-minute heat-shock at 21 hpf (D,I) never showed co-localization of hand2 with dlx3b (n=0/29) or dlx5a (n=0/21), whereas hand2 colocalized with dlx3b (n=21/35) and dlx5a (n=16/16) in hand2-MO-injected embryos (E,J). Anterior is towards the left and dorsal is upwards. Scale bar: 50 μm.
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