Figure 3
Ct-piwi1 expression patterns during embryonic and larval development. Except for cleavage stages (A-D), all animals are ventral views with anterior to the left. N is a lateral view with ventral down and anterior to the left. Stages shown are indicated in the lower-right of each panel. At the top is a developmental staging chart for C. teleta. Abbreviations: br, brain; end, endoderm; fg, foregut; hg, hindgut; mb, mesodermal bands; pgz; posterior growth zone; vnc, ventral nerve cord. (A) Expression in the cytoplasm of uncleaved zygote (arrow). (B) Expression is in both cells of a 2-cell stage embryo (arrows). (C) Animal view of a four-cell stage embryo showing expression in every cell (arrows). (D) Expression throughout the embryo (arrows). (E) Endodermal expression in a stage 3 larva. (F) Expression in the brain, foregut, and mesodermal bands. (G) Ct-piwi1 is expressed in two cell clusters on the ventral side of the trunk (black arrows), and in the brain, foregut, and mesodermal bands. (H) Expression in the brain, foregut, mesodermal bands, posterior growth zone and in two asymmetrically positioned ventro-lateral cell clusters (arrows). The left cluster is more anterior. (I) Two asymmetrically positioned ventro-lateral cell clusters with the right cluster more anterior. (J) Two bilaterally symmetric ventro-lateral cell clusters. (K) The two Ct-piwi- expressing cell clusters are located close to the midline (arrows). Expression persists in the foregut and posterior growth zone. (L) The two Ct-piwi1- expressing cell clusters are in close proximity near the ventral midline (arrows). Expression persists in the foregut and posterior growth zone. (M) By stage 9, expression is limited to a single cluster at the ventral midline (arrow) and posterior growth zone. (N) Lateral view showing expression in a single cluster in between the gut and ventral nerve cord at the foregut/hindgut boundary. Scale bar, 50 μm for all panels.