Abstract
Abstract: :
Purpose: To determine if the Slug transcription factor, which plays a role in epithelial mesenchymal transformation (EMT) during development, carcinogenesis, and cutaneous wound re–epithelialization, is also important in corneal wound re–epithelialization Methods: In Slug–lacZ mice, an in–frame insertion of the ß–galactosidase gene into the zinc finger coding region of the Slug gene inactivates the encoded Slug protein. However, the promoter of the Slug gene and the coding region for the Slug nuclear localization signal are preserved. Thus, ß–galactosidase activity of the fusion protein can be used to monitor Slug expression from its endogenous promoter and the fusion protein is detected in the nucleus. Mice possessing a single Slug–lacZ allele are phenotypically normal. Mice homozygous for the Slug–lacZ allele are functional Slug knockout mice. Slug expression was determined in normal corneal epithelium and in corneal explants from heterozygous, phenotypically normal Slug–lacZ mice. In addition, outgrowth of epithelium from corneal explants of Slug–lacZ hetrozygotes and homozygotes was compared. Results: In normal cornea, Slug was expressed in stretches of basal epithelial cells. Slug was also highly expressed in epithelial cells actively migrating from corneal explants. Epithelial cell migration from corneal explants occurred normally in explants from heterozygous Slug–lacZ mice; however, there was no epithelial cell migration from corneal explants of homozygous Slug–lacZ (knockout) mice. Conclusions: The absence of epithelial cell outgrowth from the corneal explants of Slug knockout mice indicates that Slug expression is required for corneal epithelial cell migration in vitro. Expression of Slug in basal epithelial cells of normal corneas in vivo suggests that Slug may also play a role in normal turnover of corneal epithelium.
Keywords: cornea: basic science • wound healing