FIG. 6.
Effects of R654W pRb on retinal development. (A and B) P14 retinae are immunostained to identify rod cells (arrows). Rod cell defects are produced in a mosaic pattern across the retina due to heterogeneous Chx10-cre expression. (C) Quantitation of the proportions of different cell types in dissociated P14 Chx10-cre; Rb1Lox/654 retinae and in control littermates. (D) Cone photoreceptors are produced in their correct laminar position and proportion (arrow). (E) Protein kinase C α-immunopositive bipolar cells are produced in their correct proportion and position (arrow). (F) Ectopic Chx10-immunopositive cells in the outer nuclear layer are observed (arrow). Many of these ectopic cells are weakly immunopositive (*), suggesting that they are retinal progenitor cells. (G) Ectopic Pax6-immunopositive cells in the outer nuclear layer where rods normally form (arrow). Pax6 is expressed in retinal progenitor cells and mature amacrine cells. (H) Like Rb1 null retinae, horizontal cells form ectopic processes that extend apically into the outer nuclear layer. (I) Real-time RT-PCR of P14 retinae to assess expression of the genes shown. Abbreviations: ONL, outer nuclear layer; OPL, outer plexiform layer; INL, inner nuclear layer; wt, wild type; PKC-alpha, protein kinase C α; Glu Syn, glutamine synthase; dic, differential interference contrast. Scale bars, 10 μm.