Figure 2

Apical regional patterning mRNA expression in early trochophore larvae. (A-G) are ventral views, (A’-G’) and (J-Q) are apical views, and (A”-G”) and (J’-Q’) are apical views using confocal reflection microscopy of NBT/BCIP staining (red) following in situ mRNA and fluorescent DAPI staining of nuclei (white), allowing localization of individual cells in the apical Plate. F”, I, J’, K’, L’, P’ and Q’ are high magnification apical views. Ampullary cells are demarcated with yellow dashed circle. All images are of 24 hour post-fertilization (hpf) embryos, except C, C’, D, D’, E, E’, G, G’, L, M, O, O’, which are of 20 hpf embryos. Asterisks mark the tip of the apical pole. (A) Broad apical expression of foxq2 in 24 hpf trochophores. (B) Broad apical expression of six3, excluding area encompassing apical organ and a dorsal patch of cells (demarcated with white dashed lines). (C) Fezf ventrally in apical plate. (D) Rx in dorsal and ventral domains between the six3 domain and the prototroch. (E) Otx in ring-like domain adjacent to prototroch. (F) Nk2.1 in a ventral strip of cells and in two spots flanking the crescent cells. (G, I) Otp in apical cluster and in prototroch. (H, H’) Schematized ventral and apical views at 24 hpf depicting crescent and ampullary cells and prototroch. (J) Onecut in crescent cells and in cells ventral to the ampullary cells. (K) FoxJ in the ampullary cells, crescent cells and prototroch. (K’) Antibody staining to acetylated tubulin (green) and DAPI-labeled nuclei (blue). (L) Hox1 in ampullary cells. (M) Irx in six3-negative territory and in an equatorial ring below the prototroch. (N) FgfR in a cell dorsal to the ampullary cells. (O) Noggin in a cell dorsal to the ampullary cells. (P) trpV in cells ventral to the ampullary cells. (Q) Nkx3 in a small patch of cells ventral to the ampullary cells. (Q’) Nkx3 in mechanoreceptor cells (yellow arrows).