Figure 3. Clonal analysis of neuroblasts.

(a) Lineages of neuroblasts (epithelial: colored; delaminated: white) ordered by time of division and grouped according to the division behavior -dividing before (red, top) or after (orange, bottom) delamination. Each line corresponds to a single neuroblast. Discontinued lines represent cells that were not tracked further. The x-axis displays the corresponding time of embryonic development (hpf). (b) Box plot illustrating the temporal delay in delamination between sister cells (Figure 3—figure supplement 1d). (c) Illustration of neuroblast division behavior colored as in (a). (d) Dynamic map of neuronal progenitors (orange circles) and their epithelial neighboring cells (grey circles) in the context of the whole otic vesicle (grey dots) over time; see Video 8 for the 24 hpf animation. The color intensity of cell centers depicts the position of cells along the dorsoventral axis of the otic vesicle. The map was built after following the lineages from 18 hpf to 26 hpf of all encircled cells. Note how neuroblast delamination impacts on the size and position of the progenitor domain (orange cell centers) over time. Tether cells are depicted as black circles. For this analysis, Tg[cldnb:lynGFP] Tg[Isl3:GFP] line was injected with H2B-mCherry mRNA at 1cell-stage (Tables 1–2). ID Dataset: 140426aX.

DOI: http://dx.doi.org/10.7554/eLife.22268.015

Figure 3—figure supplement 1. Spatial distribution of epithelial neuroblasts according to division behavior or delamination time.

Tg[cldnb:lynGFP] Tg[Isl3:GFP] embryo was injected with H2B-mCherry at 1cell-stage, imaged and analyzed from 18 hpf to 36.2 hpf (Table 1). Images of (a) nuclei as Maximal Intensity Projection of few orthoplanes of the ventral otic vesicle, and (b) plasma membranes as 3D-rendering are displayed. (c) Spatial distribution of neuroblasts, whose reconstructed cell centers were color-coded according to their division behavior -before or after delamination- (Figure 3). Out of 116 tracked epithelial neuroblasts, 42 divide before delamination (red), 40 do so after delamination (orange), and 34 do not divide within this time window (blue). Note that there is no preferential spatial distribution of cells for these features. (d) Reconstructed cell centers of neuroblasts (n = 131) were color-coded according to time of delamination: 18–20 hpf white, 20–22 hpf yellow, 22–24 hpf orange, 24–30 hpf red. Neuroblasts giving rise to two sister cells falling into distinct delamination intervals are shown as bicolored cell centers (n = 11). ID Dataset: 140426aX.

DOI: http://dx.doi.org/10.7554/eLife.22268.016