Retinal Cell and Molecular Biology

Dr. Bok studies mechanisms whereby membrane receptors, retinoid binding proteins, and enzymes mediate the vectorial uptake, processing and release of retinoids by the retinal pigment epithelium (RPE). He also explores mechanisms whereby the RPE cells develop the polarity required for their diverse functions.

A second major research effort involves the study of molecular mechanisms underlying degeneration of retinal photoreceptors. These degenerations come under the general disease categories of retinitis pigmentosa and macular degeneration in humans. Retinitis pigmentosa is a family of inherited blinding diseases. Macular degeneration can be either age related or inherited.

The third field of study involves photoreceptor-RPE interactions in health and disease. This includes the development of transgenic mice in which the expression of a wild-type gene or its mutant counterpart can be induced by the administration of doxycycline.

Major techniques used in Dr. Bok's research include electron microscopy, laser confocal microscopy, light and electron microscopic autoradiography, cell culture, immunocytochemistry, in situ hybridization cytochemistry, molecular cloning/sequencing and analysis of transgenic animals.

Contributions include the discovery of photoreceptor outer segment disc shedding, phagocytosis of these membranes by the RPE, the failure of this process in rat mutants (rdy), detection of membrane receptors for the uptake and release of retinoids by the RPE, transgenic rescue of inherited degeneration in mice carrying the rds mutation and the modeling of the equivalent human disease in mice through the introduction of point mutations in the mouse rds gene.