Fig. 2. The pax6-DF4 enhancer element drives expression of fluorescent proteins in transgenic lines of zebrafish. In most of the lines generated, expression of membrane-targeted fluorescent proteins was confined to the retina (A-D). Confocal images of larval zebrafish from CFP line Q11 (A) and YFP line Q14 (C) reveal that at early stages, expression within the retina is in clones of cells that span the neuroepithelium. With time, expression becomes confined to amacrine cells located in the INL with processes ramifying in the IPL. The number of labeled amacrine cells varied, but was sometimes sparse enough to allow individual amacrine cells to be visualized unambiguously (B,D). Ubiquitous expression throughout the embryo was observed in CFP line Q01 (E). In the retina of line Q01, cells in the nuclear layers were outlined and the plexiform layers appeared to be densely labeled (F).