Fig. 5. Vertical divisions producing two daughter cells that acquire different morphologies. (A-E) Five examples of daughter cells produced by vertical divisions in newborn RNECs, seen 70-96 hours after the division. Note that the two daughters differ in size and morphology. In the example shown in E, it was possible to fix and stain the explant and find the two GFP⁺ daughter cells in a confocal microscope as described for Fig. 4E. The larger daughter cell (arrow) is located in a cell layer that contains big nuclei (presumably the interneuron layer), whereas the smaller daughter cell (arrowhead) is located in a cell layer that contains small nuclei (presumably the photoreceptor layer). (F) A z-series confocal projection of a clone containing a Müller cell (arrow) and a photoreceptor (arrowhead) in a frozen section of a newborn retinal explant, observed 10 days after infection with a retrovirus encoding GFP. The section was imaged in a confocal microscope and a stacked z-series is shown. (G) Quantification of cell body size of GFP-infected photoreceptors and interneuron layer cells as measured in cryosections of retinal explants. This is the same graph as shown in Fig. 4G. (H) Cell-body sizes of pairs of daughter cells produced by vertical divisions of GFP-infected RNECs followed by video recording. The daughters of all 11 vertical divisions that were followed are shown. Note that in 9 out of 11 cases the daughter cells are different in size. The larger daughter is much larger than a photoreceptor cell and is similar in size to an interneuron layer cell. The smaller daughter is usually similar in size to a photoreceptor cell. Scale bars: 10 µm in A-D; 2 µm in E,F.