Usha P. Andley, Ph.D.

DEPARTMENT OF Ophthalmology & Visual Science
Keywords: aging, protein structure, cell cycle, proteomics, cataract

We use biochemical and cell biological approaches to understand the functions of small heat shock proteins in ocular systems. Using the lens as a model, my laboratory studies the biochemical basis of human cataract formation. Several approaches are being used at understanding the function of alpha-crystallin, a major protein of the lens and a member of the small heat shock protein family of molecular chaperones. This protein, composed of two gene products alpha-A and alpha-B, plays important roles in the lens and other tissues. Mutations in alpha-A and alpha-B crystallins form the basis of several hereditary cataracts. Our laboratory is using gene transfer and knockout models to understand the function of alpha-crystallin in the lens epithelium. Previously it was thought that alpha-A crystallin acted simply as a sink for unfolding proteins in lens fiber cells. However, recent work showed that lens epithelial cultures of alpha-A knockout mice have vastly slower growth and an altered cell cycle distribution, and these findings may explain why the alpha-A null lenses are smaller than controls. It was also found that lens epithelial cells derived from alpha-B null mice transform at a higher rate and demonstrate very much increased proliferation and genomic instability. These new finding indicate that alpha-A and alpha-B may be involved in ensuring the successful completion of the cell cycle. Studies now focus on visualizing DNA synthesizing cells in vivo in the alpha-A and alpha-B knockout mice, and to examine the interaction of alpha-A and alpha-B with other proteins. These studies use confocal microscopy, flow cytometric and biochemical techniques to study the role of alpha-crystallin. Time-lapse video microscopy is being used to visualize living cells from lenses in which one or both genes has been knocked out. We are also examining the effect of specific mutations associated with hereditary cataract on the cell protective function of alpha-crystallin. In a related project, we examine the expression pattern of these proteins in the retina. Ongoing studies on the mechanisms of cataract formation are also being pursued through gene chip microarray studies.