Figure 7
Expression pattern of Nv-Runx in adult Nematostella. Digoxigenin-labeled sense-strand and antisense-strand riboprobes corresponding to nucleotides 100–539 of the ORF (exons 1–3, which contain the Runt domain) were used to characterize the spatial expression of Runx in adult Nematostella. Similar results were obtained using a longer probe corresponding to the entire Nv-Runx transcript (not shown). A) Labeled anti-sense probes detect Nv-Runx expression in the oral region of the anemones, particularly in the ectoderm of the tentacle tips (animal on left). No specific staining was observed using sense-strand probes (animal on right). B-C) While expression was always limited to the tentacle and head region there was some background staining that varied between individual animals. Note that the dark color in the mouth of the animal depicted in panel B (arrowhead) does not represent Runx expression, since it is not detected in sections of this region. The arrowhead in Panel C reveals the strong expression at the tentacle tips. D-H) These panels show ectodermal expression of Nv-Runx in the tentacles as seen in cryostat sections of anemones after whole mount in-situ hybridization. D) Low magnification micrograph of a section through the head and tentacles, revealing general architecture as well as the location of the enlarged micrographs in E and F. Bar = 100 μm E-G) Expression of Nv-Runx in the ectoderm of the tentacles, Bars in E and F = 50 μm, in G = 20 μm, H) A thin section of a tentacle from Nematostella, stained with Methylene Blue. Numerous spirocysts (Sp) and several nematocysts (N) can be observed, as can darkly and heterogeneously stained gland cells (G) found towards the apical part of the ectoderm. The elongated cells (S) are probably sensory cells [61]. The mesoglea (Mes) is schematically marked by a dashed line. Bar = 10 μm. I) Expression of Nv-Runx in scattered cells in the ectoderm of the body wall (arrowhead). Bar = 20 μm.