Fig. 5

Characterization of two novel markers for differentiated cnidocytes. Expression of a–f nematogalectin (Ngal) mRNA and g–l γ-glutamyl transpeptidase (Ggt) mRNA during development. Onset of expression begins at/before the gastrula stage in scattered cells of the ectoderm (surface plane, insets) for both Ngal (b) and Ggt (h). Ngal is expressed in the body wall ectoderm throughout development (b–e, insets), and expression becomes dense in the developing tentacle buds (e) and tentacle tips of the polyp (f, arrow). Ggt is also expressed in the embryonic ectoderm (h–j) and presumptive tentacle buds but is absent from the body wall at later stages (k, inset) and is expressed in only few cells of the tentacle tips (l, arrow). m Ngal mRNA is co-expressed with Ncol3 mRNA in most developing cnidocytes in early-planula-stage embryos. n, o Few cells exhibit Ncol3 mRNA expression without Ngal (arrows), but p Ngal mRNA and NCOL3 protein are perfectly co-expressed. q–s Ggt mRNA is co-expressed with Ncol3 mRNA in many but not all developing cnidocytes. (Arrows in r–s indicate cells expressing Ncol3 only.) t Co-labeling of NCOL3 protein and Ggt mRNA confirms that some cnidocytes express Ncol3 without Ggt (arrows). Images in a–l are DIC micrographs, images m and q are 3D renderings from confocal z-stacks, and images n–p and r–t are individual optical sections