In the article “Trk C Signaling Is Required for Retinal Progenitor Cell Proliferation,” by Indranil Das, Janet R. Sparrow, Michelle I. Lin, Evangeline Shih, Takashi Mikawa, and Barbara L. Hempstead, which appeared on pages 2887–2895 of the April 15, 2000 issue, Figure 1 was incorrectly printed as a black and white figure. The correct color version of the figure, as well as the legend, is printed here.
Expression of NT-3 and trk C receptors in E5 chick eye. A, E5 frozen sections were immunostained with antisera to NT-3 using a VIP chromogenic substrate (red) and counterstained with hematoxylin (blue). Labeling for NT-3 is most prominent adjacent to the retinal pigment epithelium in an area of retina where retinal progenitors are mitotically active. Labeling is also detected in the innermost retina. PE, Pigmented epithelium; NR, neural retina. B, In the control section, labeling was blocked by addition of immunizing peptide. Scale bar, 10 μm. C, Total RNA from chick eyes harvested at E5 was subjected to RT-PCR using primers specific for full-length trk C. − and + indicate the absence and presence, respectively, of reverse transcriptase during cDNA synthesis as a control for genomic DNA contamination. The full-length trk C primers generated a single band of the expected molecular size (772 bp).