Fig. 7

Over-expression of msgn1 can exert PSM-inducing activity. (A and B) Lateral views of control (A) and msgn1 mRNA (200 pg)-injected (B) embryos at the 16-somite stage. (C)-(R) Marker analysis of msgn1 mRNA over-expressed embryo. Control (C, E, G, I, K, M, O, and Q) and msgn1 mRNA-injected (D, F, H, J, L, N, P, and R) zebrafish embryos hybridized with ntl (C-F), flh (G-J), tbx24 (K-N), wnt8 (O and P) or pax2.1 (Q and R) probe. Stage of the embryo is indicated at the left bottom in each photo. Dorsal views of axial region (C, D, G, H, K, and L), tailbud region (E, F, I, J, and M-P) and trunk region (Q and R) are shown. In the axial region, significantly reduced expression of ntl (C and D) and flh (G and H), and ectopic expression of tbx24 (K and L, shown with a bracket) are observed at the mid-gastrulation stage (80% epiboly). Reduced axial expression of ntl (E and F) and flh (I and J), and ectopic axial expression of tbx24 in the posterior tip (bracket) and axial region (arrowhead) (M and N), continued at the early-somite stage (3 somites, 1 somite, and 5 somites, respectively). The expressions of ntl (E and F) and wnt8 (O and P) in the tailbud were severely reduced in the msgn1-injected embryo at the early somite stage (3 somites). The expression of tbx24 was expanded to the posterior tip of the tailbud (M and N). However, pronephric expression of pax2.1 was not affected (Q and R).