Fig. 6.

Expression of drgx, otx and gata in Clytia. (a–d) Ch-drgx expression in the tentacle ectoderm of polyps. (b–d). In early medusa buds, it is expressed in the ectoderm covering the radial tubes (stippled line) externally. In the late medusa bud, Ch-drgx is expressed in a narrow band around the future bell rim. In free medusa, Chdrgx is expressed at the bell rim. (e–h) Chotx is expressed in polyps at the tentacle base ectoderm and in the mouth tip. In early medusa buds, Ch-otx is expressed in the lateral parts of the entocodon (f, stippled line marks radial tube). In late medusa buds, Ch-otx expression is located in the entire ectodermal subumbrella with strongest expression in the inner bell rim but absent from the striated muscle-differentiating areas. In young medusa Ch-otx is found in diffuse cell clusters in the entire subumbrella and in statocysts (red arrowhead). (i–m) Ch-gata is expressed in the body column ectoderm up to the tentacle bases of the polyp (arrowheads). Early medusa bud express Ch-gata in the basal outer ectoderm below the level of the radial tubes (arrowheads). Late medusa buds show Ch-gata expression in the entire subumbrellar ectoderm and weaker staining in the exumbrellar ectoderm but absence of Ch-gata signal in the striated muscle sheet. Additional Ch-gata expression in the developing nerve rings at the bell rim (red arrowhead). In free medusae, Ch-gata is exclusively expressed in single cells at the bell rim, presumably in neurons (m, red arrowhead, insert). (n–p) Schematic summary of expression patterns of ectodermal polyp tentacle marker genes (right halves) and general morphology (left halves) in polyps, early medusa buds and late medusa buds. Only ectodermal tissue is shown for better clarity