Purchase this article with an account.
J.-H. Joo, Y. Kim, N. W. Dunn, S. P. Sugrue; Pinin is Required for the Expression of Pdgfr During the Development of Mouse Anterior Eye Segment. Invest. Ophthalmol. Vis. Sci. 2010;51(13):703.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
Previously, we demonstrated that Pinin (Pnn) is essential for the differentiation of corneal epithelial cells in mice. In this study, we investigated Pnn’s function and its underlying mechanism during early embryonic development of anterior eye segment.
Conditional inactivation of Pnn in the developing ocular surface ectoderm was achieved by utilizing Pax6 (lens)-Cre mice. Development of anterior eye segment in mutant mice was studied by histological, immunohistochemical, and biochemical assays.
Inactivation of Pnn by Pax6-Cre transgene resulted in disrupted anterior eye segment development, eventually leading to aphakia in postnatal mutant mice. At early stages of eye development, the mutant eyes displayed delayed lens vesicle separation from the corneal epithelium, exhibiting the persistent presence of lens stalk observed as late as E13.5. The elongation of primary lens fiber cells appeared to be disrupted and the number of anterior lens epithelial cells was significantly lower than those of control embryos, while no considerable increase in apoptotic cell death was detected. Interestingly, the mutant lens showed similar levels and/or patterns of Pax6, Pitx3, Prox1, and Foxe3 expression to the control littermates. However, we discovered that the mutant eyes express significantly downregulated level of Pdgfrα in developing lens at E11.5 and thereafter. Since Pnn has been previously shown to play a role in the transcriptional regulation by modulating the activity of transcriptional co-repressor CtBP proteins, we examined promoter activity of Pdgfrα in Pnn-depleted embryonic stem (ES) cells which also exhibited significant downregulation of Pdgfrα. The level of histone H3 trimethylated at lysine 4 (H3K4me3), a general marker for active chromatin and gene expression, was markedly reduced in the Pdgfrα promoter area in Pnn-deficient ES cells. Furthermore, CtBP2, a direct interaction partner of Pnn, was found to be present on the promoter of Pdgfrα, suggesting the possibility of Pnn’s involvement in the regulation of Pdgfrα promoter activity during mouse lens development.
Our study demonstrates that Pnn is essential for the development of mouse anterior eye segment and that Pnn may act through modulating promoter activity of Pdgfrα during lens development.
This PDF is available to Subscribers Only