Weak expression of TagRFP was detected in cells in the ganglion cell layer (GCL) in the retina of ubb:Cre-GFP; shhact/+ embryos but not in shhact/+ and ubb:Cre-GFP embryos. Confocal projections of z-stacks are shown in three panels from the right, and the bright field image of in situ hybridization of shha mRNA is shown in the far left panel. Dotted lines, approximate border of the GCL. Scale bar, 50 μm.