PURPOSE Overloading of unfolded or misfolded proteins in the endoplasmic reticulum (ER) can cause ER stress and activate the unfolded protein response (UPR) in the cell. The authors tested whether transgene overexpression in the mouse lens would activate the UPR. METHODS Transgenic mice expressing proteins that either enter the ER secretory pathway or are synthesized in cytosol were selected....

Lens fiber cells are transparent, highly elongated, epithelial cells. Because of their unusual length these cells represent a novel model system to investigate aspects of epithelial cell polarity. In this study, we examined the fiber cell basal membrane complex (BMC). The BMC anchors fiber cells to the lens capsule and facilitates their migration across the capsule. Confocal microscopy revealed...

PURPOSE Activation of stress pathways is a primary cause of age-related cataracts. Our laboratory previously developed a lens cataract model in which activation of the p38 kinase/Src family kinase (SFK) stress-signaling pathway is responsible for the induction of cortical opacities. Here, we use this model to investigate further the mechanism of stress-induced cataract. METHODS Cortical catar...

PURPOSE To investigate whether a histologic link exists between osmotic fiber cell swelling and cortical tissue liquefaction in experimentally induced diabetic and galactosemic cataractogenesis of the rat lens. METHODS Confocal laser scanning microscopy, in conjunction with specific membrane labels and correlative transmission electron microscopy, was used to image large cortical areas with p...

The lens is proposed to have an internal microcirculation system consisting of continuously circulating ionic fluxes that play an essential role in maintaining lens transparency. One of the key components of this system is the sodium leak conductance. Here we investigate the contribution of Cx46 hemichannels to the basal membrane permeability of peripheral fiber cells isolated from transgenic m...

PURPOSE To characterize the constitutively activated epidermal growth factor receptor in a lens epithelial cell population experiencing initial stages of lens fiber formation, the chick lens annular pad. METHODS Phosphotyrosine levels of the receptor were examined with western blot analysis and immunoprecipitation after ligand stimulation. Endogenous receptor ligands were immunologically iden...

PURPOSE A distinct subset of genes, so-called "late fiber genes," is expressed in cells bordering the central, organelle-free zone (OFZ) of the lens. The purpose of this study was to identify additional members of this group. METHODS Fiber cells were harvested from various layers of the lens by laser micro-dissection and subjected to microarray, in situ hybridization, and Western blot analysi...

PURPOSE Lens fiber cell membranes contain aquaporin-0 (AQP0), which constitutes approximately 50% of the total fiber cell membrane proteins and has a dual function as a water channel protein and an adhesion molecule. Fiber cell membranes also develop an elaborate interlocking system that is required for maintaining structural order, stability, and lens transparency. Herein, we used an AQP0-defi...

PURPOSE To evaluate the expression and location of integrin-linked kinase (ILK) within the mouse lens and to characterize the role of this protein during mouse lens epithelial cells (LEC) differentiation in vitro. METHODS Transcription levels of ILK mRNA were determined by RT-PCR in cultured cells and lens tissue. ILK protein was detected by immunoblotting, immunocytochemistry, immunohistoche...

(1) Dorsal irises from normal and lentectomized eyes of the newt Notophthalmus viridescens were cultured in vitro in the presence of colchicine (1-25 x 10~ to 2-5 x 10~ M), vinblastine sulfate (4-4xlO~) and cytochalasin B (20/tg/ml). Explants were treated for 24 h and implanted into host eyes of previously lentectomized newts. (2) In regenerates treated with colchicine at stages prior to the on...