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Fig. S3
Centrosomes of BCs are clustered at the OPL
A. In vivo confocal images of a 2 dpf retina in which centrosomes (centrin4 mRNA) and cellular membranes (BODIPY‐Texas Red) are labeled. The outer part of the INL is largely devoid of centrosomes. The emergence of the OPL (region to the right of the arrowhead) coincides with the clustering of centrosomes in this location. Solid gray line indicates the apical surface. Orange and cyan bars above the images represent unlaminated and laminated parts of the retina, respectively. Scale bar: 10 μm.
B. In vivo confocal images of a 2 dpf retina in which centrosomes (centrin4 mRNA) and a subset of BCs (Q19) are labeled. BC somata are devoid of centrosomes. The relocation of BC centrosomes from the apical surface (solid gray line) to the OPL coincides with the retraction of the apical process of BCs (arrowhead). Orange and cyan bars above the images represent unlaminated and laminated parts of the retina, respectively. Scale bar: 10 μm.
C. Confocal in vivo images of a 3 dpf retina with an isolated BC, in which the centrosome and cellular membranes are labeled with YFP and cerulean, respectively (plasmid encoding UAS:centrin4‐YFP/UAS:memCerulean was injected into Q26). The centrosome (green) is localized to the dendritic tuft at the OPL rather than in the soma. Scale bar: 5 μm.
D. Scheme illustrating distinct developmental steps (nucleokinesis, centrosome relocation, apical process retraction, transient arborizations of the apical process in the OPL and mitosis at the INL/OPL interface) for the vsx1+ progenitor from Fig 3D and E, observed by time‐lapse imaging. Nucleokinesis trajectories of the cell are color coded to indicate the local cytoarchitecture of the retina when these events took place (orange: unlaminated; cyan: laminated).