Figure 5

Expression patterns of Tt.Six1/2 and Tt.FoxC. 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.Six1/2 is expressed in the archenteron walls and lateral ectoderm (black arrowheads) in the late gastrula stage and in the apical, mantle, and pedicle lobe mesoderm and mantle lobe ectoderm (black arrowheads) in the larval stages. (I-P) Tt.FoxC expression is first detected in the radial gastrula in the anterior of the archenteron wall and broadly in the adjacent anterior ectoderm. In the asymmetric gastrula, expression persists in the anterior archenteron wall and anterior ectodermal expression has resolved into two lateral bands that extend along the animal-vegetal axis. Ectodermal expression is out of the plane of focus in the lateral view. In larval stages, expression is in the ventral anterior and posterior mesoderm. In the early larval stage, a ventral band of apical ectoderm is positioned near the anterior of the blastopore, and in the late gastrula stage, ectodermal expression is expanded dorsally to form a circumferential ring just anterior of the ciliary band (black arrowheads).