Figure 9

Expression patterns of Tt.FoxD and Tt.noggin. All images are oriented with anterior to the left. Panels (A-D) and (I-L) are lateral views. Panels (E, F) and (M, N) are blastoporal views. Panels (G, H) and (O, P) are ventral views. For detailed descriptions of expression patterns, see text. (A-H) Tt.FoxD is expressed in a narrow band of cells at the border of the archenteron wall and roof in the radial gastrula (black arrows). A second band of expression is present in ectodermal cells at the anterior of the animal half of the embryo (black arrowheads). In the larval stages, Tt.FoxD is expressed in two bands of the mesoderm in the mantle lobe (black arrows), which converge ventromedially in the pedicle lobe (white arrows). In the asymmetric gastrula and larval stages, a broad band of ectodermal expression is present on the ventral side just anterior of the blastopore. (I-P) Tt.noggin is expressed in the blastopore lip (black arrow) and the ectodermal animal cap (black arrowhead) of the radial gastrula. Distinct domains of expression are present in the lateral (white arrows) and posterior (black arrows) regions of the blastopore lip in the asymmetric gastrula. Expression of Tt.noggin in the ventral mesoderm of the forming mantle (white arrows) and pedicle lobes (white arrowheads) in the early larva expands to form a single broad domain of expression in the ventromedial mesoderm of the late larva. Additional domains of expression also appear in the ectodermal portions of the chaetal sacs (open white arrowheads) in the late larva.