FIGURE SUMMARY
Title

Single-cell analysis of somatotopic map formation in the zebrafish lateral line system

Authors
Sato, A., Koshida, S., and Takeda, H.
Source
Full text @ Dev. Dyn.

Somatotopic ganglion organization in the posterior lateral line (PLL) ganglion of a zebrafish embryo. A-H: Confocal images of the PLL ganglion of 6 days postfertilization (dpf; A-D) and 54 hours postfertilization (hpf; E-H) Tol 047 embryos that had been retrogradely labeled from different inter-neuromast regions; between the fourth (described as "L4" on the top row) and fifth (L5) PLL neuromast (A, E), third (L3) and fourth (L4) neuromast (B, F), second (L2) and third (L3) neuromast (C, G), and first (L1) and second (L2) neuromast (D, H). In some cases, exceptional cells were observed (white arrows). I: Quantification of somatotopic map precision at 54 hpf, 6 dpf, and 7 dpf. The number of total labeled cells and exceptional cells were counted and the proportion of exceptional cells was thus calculated. Sample numbers are shown in each column. Error bars are the SEM. **P < 0.05, *P < 0.2 (student′s t-test corrected for multiple comparisons). Scale bars = 10 μm.

Diversity of posterior lateral line (PLL) neurons in terms of the position of their growth cone. A-C: Three different mosaic embryos expressing DsRed (magenta) in a single PLL neuron in Tol047 embryos. A-C: The scheme on the top indicates the regions where the images were taken, i.e., near the PLL ganglion (A), on the PLL nerve (B), and at the leading edge of the PLL nerve, that is, in the primordium (C). All images were taken at 32 hpf. D: Distribution of individual growth cones. Black bars indicate the relative position of each growth cone. The relative position was quantified according to the following equation: relative position = somite number of labeled growth cone / somite number of tip of PLL nerve (n = 12). Gray area shows the primordium. Scale bars = 10 μm.

Morphology of the growth cones of individual posterior lateral line (PLL) neurons. A: Individual growth cones in nine different mosaic embryos. The type of each growth cone (type A or B) is denoted in the lower left corners. The numbers in the lower right corners indicate the complexity index (PΛ2/A; square of the perimeter divided by the area) of each growth cone. All images were taken at the same original magnification. B: Average complexity index ± SEM for the growth cones of type A (n = 15) and type B (n = 23) neurons (*P < 0.005; Student′s t-test corrected for multiple comparisons). Scale bar = 10 μm.

Green fluorescent protein (GFP) expression pattern of the enhancer trap zebrafish strain, Tol 047. A-I: GFP (A,D,G) and HuC/D (B,E,H, immunostaining) expression in the posterior lateral line (PLL) ganglion of 24 hours postfertilization (hpf; A-C), 3 days postfertilization (dpf; D-F) and 6 dpf (G-I) Tol 047 embryos, and merged image (C, F, I). The cells expressing GFP and HuC/D are corresponding. Scale bars = 10 μm.

Distribution of newly differentiated neurons in the posterior lateral line (PLL) ganglion. A,C: The neurons labeled magenta has been differentiated and photoconverted at 30 hours postfertilization (hpf; A) and 5 days postfertilization (dpf; C). The cells expressing only green Kaede are newly added neurons within 24 hr just before the observation. B,D: Z-stack images of newly added neurons abstracted from the raw images (A, C) by image processing. The outline of PLL ganglion is indicated by a white dotted line. Scale bars = 10 μm.

Acknowledgments
This image is the copyrighted work of the attributed author or publisher, and ZFIN has permission only to display this image to its users. Additional permissions should be obtained from the applicable author or publisher of the image. Full text @ Dev. Dyn.