Figure S5.

Anatomico-molecular analysis of the mushroom bodies at 6 dpf, related to Figure 6

A: Illustration of the identification of mushroom bodies peduncles from the juvenile worm, where both the cellular and neuropil structures are clearly recognizable, to the 6 dpf Platynereis. The first three panels are maximum projection images of confocal stacks, obtained from acetylated tubulin immunostainings. The fourth panel is obtained from the EM dataset. The fifth panel is a simplified illustration of the relevant structures shown in the rest of the panels. All panels are composed of two views at different dorso-ventral locations to highlight the dorsal and ventral peduncles, indicated with arrowheads. B: Heatmap for all cells that constitute the mushroom bodies (MB) ganglia. Only the 75 most variable genes are shown. Cells are grouped into clusters (genetic territories; see methods), and hierarchically ordered within each cluster. The order of the MB clusters in the heatmap is established using hierarchical clustering of cluster expression means. Rows are ordered by gene modules as in Figure 6G. Genes within each module are ordered by specificity values of each gene (see methods). On the top of the heatmap, blue indicates cells positive for proliferative EdU stainings done at distinct developmental stages, as well as cells that are traced, and those found to show bipolar projections (sensory endings). Genes starting with ‘loc’ are GPCR-related but without clearly identified homologs. C. 3D views of the MB genetic territories, each color-coded according to their colors in the heatmap. The neuropil is plotted in gray, and the mesh of the entire mushroom body ganglion is plotted as well for reference. The top row shows the ventral view and the bottom row the anterio-dorsal view. The regions shown are specified in the models shown in the left. D. EM slices at the level of the two peduncles. E. Frontal 3D view of the cells traced for the mushroom bodies ganglia (see Figure 6G). In D and E, cells are color-coded according to which MB genetic territory they belong to. F. Anterio-dorsal 3D view of the traced dark cells (see section on cell morphology; Figures 3 and S2).