Figure 4. In situ hybridization for PEDF mRNA (dark reaction product) in fetal macaque retina. Layers of the retina are indicated by the vertical brackets. Vessel profiles are indicated in C and D by oblique arrows. A, B: At Fd 80, higher levels of PEDF expression were detected in the GCL at the incipient fovea (A) compared with a location near the optic disc (B). PEDF levels were low in the RPE at Fd 80. Labeled cells in the IPL of A are most likely displaced ganglion cells which are common in central retina at this age. C, D: In the Fd 150 fovea (C), relatively high levels of PEDF mRNA are present in the GCL compared with levels in the GCL near the optic disc (D). Inset shows increased PEDF expression in the RPE at Fd 150 compared with Fd 80 (see A and B). Abbreviations: ganglion cell layer (GCL); inner nuclear layer (INL); inner plexiform layer (IPL); outer nuclear layer (ONL); outer plexiform layer (OPL); nerve fiber layer (NFL); retinal pigmented epithelium (RPE).