Fig. 6

MAPK-P and T4-binding site distribution in Pisaster ochraceus gastrulae. Gastrulae were exposed for 90 min prior to fixation. Gastrulae were stained with Hoechst 33342 (blue; nuclei), rhodamine-conjugated T4 (red; T4-binding sites), and an antibody for phosphorylated MAPK (green, P-MAPK). A Maximum intensity projection of confocal fluorescent image of control P.o. gastrula. B Maximum intensity projection of confocal fluorescent image of gastrula exposed to T4 for 90 min. C–C’ Focal slice of control gastrula showing tip of the archenteron and developing coelomic pouches. D-D’ Focal slice of T4-exposed gastrula showing tip of the archenteron and developing coelomic pouches. MAPK phosphorylation patterns are similar to the control gastrula. Few to no T4-binding sites were observed in any early P. ochraceus gastrulae. E T4 did not significantly increase MAPK phosphorylation in P.o. gastrulae relative to the control. RGD peptide decreased MAPK phosphorylation relative to the control (n = 5, p < 0.05). Asterisk indicates significant difference from the control. c: Coelomic pouch, ar: Archenteron (gut)