Figure 6

Molecular fingerprint of Platynereis apical organ cell types. (A) EdU incorporation (white) in dividing cells between 22 and 24 hours post-fertilization (hpf) (apical view). Central EdU-negative cells (magenta) represent post-mitotic apical organ cells. Inset: 5 μm z-projection of apical organ. (B) Acetylated tubulin staining at 30 hpf, apical view. Crescent cells located dorsal to ampullary tuft cells. Inset: Cilia of the putative mechanosensory cells (arrowhead). (C) Lateral view of ampullary tuft cells, acetylated tubulin (green) and DAPI staining (blue), 30 hpf. (D) Serotoninergic cells of the apical organ stained with an anti-5HT antibody, 48 hpf. White arrow indicates serotonergic interneuron (magenta in schematic). (E) Four otp + peptidergic flask-shaped cell (numbers) at 48 hpf (apical view). One of these labeled by an FMRFamide antibody. In schematic, numbers indicate otp + cells and the FMRFamidergic cell is in cyan. (F) Lateral view of putative mechanosensory cells, 48 hpf (arrowheads: stiff curly tips of the sensory cilia). (G, H) Mutually exclusive gene expression at 48 hpf, 23 μm z-projection of averaged expression patterns obtained with profiling by image registration (PrImR). (I) Cell types of the otp + domain. The image shows non-overlapping expression of markers of each cell as deduced from PrImR, 11 μm z-projection of average expression patterns. (J) 4 μm z-projection of the average axonal scaffold at 48 hpf, showing the deep position of the two ampullary cells surrounded by neuropil. (K) Expression of peropsin at 24 hpf (L) Expression of c-opsin1 at 20 hpf. (M) Hierarchical clustering of the molecular fingerprint of individual cell types identified within the apical organ region and of the prototroch for comparison. Expression in magenta. Asterisk indicates the two ampullary tuft cells, red arrows indicate crescent cells and yellow arrowheads indicate cilia of two putative mechanosensory cells. In panels B-H, gene expression is in red, DAPI staining in blue and tubulin staining in green unless otherwise specified. Panels C-F, scale bar is 10 μm.