Actin filament localization and distribution in the young adult mouse cornea: a correlative immunofluorescent and cytochemical study

The localization and distribution of actin filaments was determined in the corneal epithelium and endothelium of the young adult Swiss Webster mouse by correlative indirect immunofluorescence using rabbit anti-skeletal muscle actin antiserum and by in situ labelling with heavy meromyosin subfragment-1 (HMM-S1). A diffuse fluorescent staining was observed in the cytoplasm of epithelial and endothelial cells and in stromal keratocytes. In addition, a highly fluorescent punctate cytoplasmic staining was seen only in the corneal epithelium. Ultrastructurally, HMM-S1 decorated actin filament bundles were generally distributed within the cytoplasm of glycerinated superficial, wing and basal epithelial cells and within pedicle-like processes on the posterior surface of superficial and wing cells. Actin filament bundles also were seen in close association with intermediate filament bundles in the epithelium. HMM-S1 labelled filaments were observed in the endothelial cytoplasm anteriorly near Descemet's membrane, posteriorly near the anterior chamber and adjacent to lateral cell borders. Actin filaments in epithelial and endothelial cells appeared to insert into the plasma membrane.