Fig. 3. Both Pax3 and Zic1 are required for neural crest determination in vivo. Pax3-MO (20 ng/cell; A-F), Zic1-MO (20 ng/cell; G-L), Foxd3-MO (20 ng/cell; M-O), Msx1-MO (50 ng/cell; P-R) or dnBMPR (200 pg/cell; S-U) were injected unilaterally into the animal blastomeres of eight-cell-stage embryos. Foxd3 expression suppressed by Pax3-MO (A) was rescued by Pax3 mRNA (C), but not by Zic1 nor Msx1 (E,F). Zic1-MO-induced suppression of Foxd3 (G) was reversed by Zic1 mRNA (I), but not by Pax3 nor Msx1 (K,L). Msx1-MO suppresses the expression of Foxd3 but not of Pax3 and Zic1 (P-R). Foxd3 expression, upregulated by dnBMPR (S), was suppressed by Pax3-MO and Zic1-MO (T,U). Whole-mount in situ hybridization with Foxd3 (A,C,E-G,I,K,L,P,S-U), Slug (B,H,M), Pax3 (J,N,Q) and Zic1 (D,O,R) probes.