Fig. 3

Retinal cell proliferation and Bruch’s membrane formation are both normal in blowout. (A, B) Wild-type (A) and blw (B) embryos were exposed to BrdU from 42 hpf to 48 hpf and immediately sacrificed. BrdU positive cells (red) are observed throughout the retinas of wild-type and blw mutant embryos in similar proportions (C; no statistical difference—Fisher’s exact test). Additional exposure periods (24–36 hpf, 72–96 hpf) resulted in identical regions of proliferation in the retinas of wild-type and blw mutants (data not shown). (D, E) Bruch’s membrane, a basement membrane at the posterior of the eye, highly expresses the laminin-111 protein (Lee et al., 2007). Shown here are images of 12 μm cryosections from wild-type (D) and blw (E) whole-mount embryos stained for laminin-111 protein at 48 hpf. Laminin-111 levels and distribution are similar between wild-type and blw embryos. The optic stalk appears abnormal in blw, as it remains connected to the retina at 48 hpf (arrows in panels B, E), while in wild-type siblings it has degenerated. Transverse sections, dorsal is up in all images.