Abstract
Abstract: :
Purpose:To describe the ocular malformations in a transgenic mouse lacking the Ski gene. This gene encodes a nuclear protein that regulates gene expression in association with other proteins. Ski-deficient mice have severe facial clefting, neural tube abnormalities and muscle defects. Details of ocular abnormalities have not been previously described in this mouse model. Methods: To date we have examined the histological findings in the eyes of 4 Ski -/- mice and compared them to their unaffected heterozygous littermates. Results:The findings in the 4 animals have been consistent, and have not been observed in heterozygotes. These abnormalities include: (1) externally visible iris coloboma and/or iris hypoplasia; (2) micorphthalmia; (3) failure of separation of the lens from the surface ectoderm and its adherence to the cornea (Peters’ anomaly); (4) cataracts; (5) significant residual and hyperplastic remnants of the hyaloid system of blood vessels and tunica vasculosa lentis behind the lens (Persistent Hyperplastic Primary Vitreous); (6) retinal coloboma with or without optic nerve coloboma; and (7) frequent neuroretinal folds and evidence of retinal dysplasia. The anterior chamber angles were very poorly formed and suggested anterior segment dysgenesis. Conclusion:Ocular defects in Ski -/- mice resemble human malformations caused by developmental gene defects. Many of these defects including Peters' anomaly, anterior segment dysgenesis, iris hypoplasia, and retinal folds may result from decreased expression of developmental genes involved in normal ocular embryogenesis.It is probable that Ski interacts with some of these genes and modulates their transcription; its absence therefore might lead to a combination of malformations that would have otherwise occurred individually. Disturbances in Pax6, Pax2, RA and or other gene signaling in Ski knockouts are possibly responsible for the observed malformations.
Keywords: 316 animal model • 629 vitreous • 606 transgenics/knock-outs