Fig. 5.

tbx2b^p25bbtl acts cell-autonomously. Genetic chimeras were generated by blastula transplantation and allowed to develop to 80 hpf. Donor cells were labeled by rhodamine-dextran (red); tbx2b^p25bbtl deficient rods expressed the XOPS-GFP transgene. Chimeras were whole-mount immunolabeled for UV opsin (A and B) (blue) and for rods (A) (green). (A and B) Stacks of confocal images taken tangential to the photoreceptor cell layer and in the orthogonal plane (insets). (A) WT donor cells (red) located in the ONL of tbx2b^p25bbtl hosts frequently colabel for the UV opsin (inset). (B) tbx2b^p25bbtl mutant donor cells (red) in the ONL of WT hosts frequently differentiate as GFP⁺ rods and rarely label for the UV opsin. Inset shows dextran/GFP positive rods neighboring UV opsin-positive/dextran negative cone outer segments.