Purchase this article with an account.
D.M. Defoe, L.B. S. Adams, J. Sun, S.N. Wisecarver, E.M. Levine; Defects in RPE Cell Proliferation and Retinal Attachment Characterize p27(Kip1)–Null Mice . Invest. Ophthalmol. Vis. Sci. 2005;46(13):1635.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
Purpose: To better understand the role that the negative cell cycle regulator p27(Kip1) plays in controlling proliferation of the retinal pigment epithelium (RPE). Methods: Ocular tissues were obtained from wild–type and p27(Kip1)–null mice at several postnatal stages. Following aldehyde fixation, eyes were either processed intact for JB–4 histology and electron microscopy or dissected as posterior eyecups for flat–mounting after neural retina removal. Epithelial flat–mounts were labeled with AlexaFluor 488–phalloidin and propidium iodide to visualize cell boundaries and nuclei, respectively. Results: Morphometric analysis using transverse sections revealed a ∼100% increase in nuclear density and a ∼30% increase in thickness (apical to basal) for mutant vs. normal epithelia at postnatal day 35 (P35). These changes were not restricted to central or peripheral regions, and were uncorrelated with focal areas of dysplasia seen in the mutant neural retina. At P7, when the increase in RPE nuclear density was nearly complete, cell density had increased by only 36%. Surprisingly, while RPE cells from null animals were indistinguishable ultrastructurally from those of the wild–type, interdigitation of their microvillous processes with outer segments was incomplete. Conclusions: The absence of a functional Kip1 gene results in enhanced RPE nuclear division, without a commensurate increase in cell division. Although mutant epithelial cells appear normal, their interaction with the neural retina is compromised.
This PDF is available to Subscribers Only