Fig. 3

i>Gcm-2 is required for the elaboration of the internal gill buds from the pharyngeal pouches in zebrafish. Zebrafish embryos were injected at the one-cell stage with either control or antisense Gcm-2 MOs. The embryos were then analyzed at day 5 for the presence of internal gill buds. (A–C) Five-day-old zebrafish larva injected with control MO. (A) Nomarski view of the pharyngeal region of a day-5 embryo injected with the control MO. The internal gill buds protruding from the pharyngeal pouches are clearly evident (arrowheads). (B) Embryo injected with control MO hybridized for Gcm-2. Gcm-2-expressing internal gill buds can be clearly seen protruding from the pharyngeal pouches. (C) Embryo injected with control MO, showing normal pharyngeal pouch formation as judged by Pax-9a expression. Each pharyngeal pouch is indicated by an arrowhead. (D–F) Five-day-old zebrafish larva injected with Gcm-2 antisense MO. (D) Nomarski view of the pharyngeal region of a E5 embryo injected with the antisense Gcm-2 MO. There are no internal gill buds protruding from the pharyngeal pouches. (E) Embryo injected with the antisense Gcm-2 MO hybridized for Gcm-2. There are no Gcm-2-expressing internal gill buds protruding from the pharyngeal pouches. (F) Embryo injected with the antisense Gcm-2 MO, showing normal pharyngeal pouch formation as judged by Pax-9a expression. Each pharyngeal pouch is indicated by an arrowhead. EY, eye; YK, yolk. Anterior is to left and ventral is to the bottom.