Figure 2

Expression of Otx, Blimp1, Bra, Nkx2.1a, FoxAB and Gsc during embryogenesis in Capitella teleta . Each row shows expression (blue color) for the single gene listed at the left margin. The approximate stage of development for the embryos in each column is listed at the top margin. The orientation of each embryo is listed at the bottom right corner of every panel (anm, animal view; veg, vegetal view; vent, ventral view). In embryos with approximately 28 to 33 cells, the D quadrant is toward the bottom of each panel. Yellow dotted lines indicate the position of the blastopore. M is the animal view of L; R is the animal view of Q. Anterior is to the left in all Stage 3 embryos. (A-E) Ct-otx is expressed in each macromere (black arrows) and micromere (white arrows) of 8-cell embryos (A), in micromeres (black arrows) encircling the animal pole (B-D), in both anterior (black arrowheads) and posterior (white arrowheads) ectoderm and within and around the blastopore (white arrows) of gastrulae (E). (F-J) Ct-blimp1 is not detected in macromeres (dashed black arrow) or micromeres (dashed white arrow) of 8-cell embryos (F); Ct-blimp1 is expressed in macromeres (black arrow) and 4q micromeres (white arrow) of 28- to 33-cell embryos (G), in vegetal cells (white arrows) of stage 2 and stage 3 embryos (H-I), and in the endoderm (J). (K-O) Ct-bra is expressed in each macromere (black arrows) and micromere (white arrows) of 8-cell embryos (K), in macromeres (black arrows) and micromeres (white arrows) in each quadrant of 28- to 33-cell embryos (L-M), anterior to the blastopore (short white arrows) and around the blastopore (dashed black arrows) of gastrulae (N), and on the ventral anterior surface of late gastrulae (O). (P-T) Ct-nkx2.1a is expressed in each macromere (black arrows) and micromere (white arrows) of 8-cell embryos (P), in macromeres (black arrows) and micromeres (white arrows) of 28- to 33-cell embryos (Q-R), along the left and right sides of the blastopore (S), and in both anterior ectoderm (black arrowheads) and endoderm (white arrows) of late gastrulae (T). (U-Y) Ct-foxAB is not detected in macromeres (dashed black arrow) or micromeres (dashed white arrow) of 8-cell embryos (U); Ct-foxAB is expressed in a single D-quadrant cell (white arrow) at the 28-cell stage (V), in each quadrant (white arrows) on the animal hemisphere of stage 2 (W), outside the blastopore (white arrows) in vegetal micromeres (X), and in anterior surface cells (white arrows) encircling the site of stomodeum formation (Y). (A’-E’) Ct-gsc is not detected in macromeres (dashed black arrow) or micromeres (dashed white arrow) of 8-cell embryos (A’); Ct-gsc is expressed in two animal micromeres (white arrows) within embryos of approximately 28 cells (B’), in each quadrant (white arrows) on the animal hemisphere of stage 2 (C’), in several micromeres (white arrows) anterior to the blastopore (D’) and in micromeres (white arrows) on the anterior surface of late gastrulae (E’). bp, blastopore; St, stage. The image in each panel was created by combining micrographs from a series of focal planes.