Fig. 7. Establishment of the macromolecular permeable pathway in the core of the lens during embryonic development. (A) At E14, GFP is expressed in a mosaic pattern. In equatorial sections, discretely labeled individual fiber cells are evident, scattered throughout the lens. This section was colabeled with fluorescent phalloidin (red) to visualize the organization of non-GFP-expressing cells (red). (B) In midsagittal sections, the fiber mass has a striped appearance, due to the juxtaposition of GFP-expressing and nonexpressing cells. (C) By E16, the fluorescence labeling pattern had transformed, such that the central fiber cells (situated between the arrows) are now uniformly labeled. (D) The uniformly fluorescent core region is also evident in mid-sagittal sections. Note that the region of uniform fluorescence contains fiber cells (arrows) that have recently detached from the posterior capsule. c, cornea; ep, lens epithelium. Bar, 50 µm.