The laboratories focus is on structure and function of vertebrate retina. There three general research areas. The first involves studying the role of voltage gated calcium channels in retinal development. Mouse lines with various calcium channels inactivated by gene targeting are being studied. One of the knockout lines lacks neurotransmitter release in photoreceptor cells and this leads to a failure of normal synaptogenesis in the outer plexiform layer of the retina. This defect occurs early in development. Research focuses on gene expression during development in the mutant mice in an attempt to determine which genes are critical for normal synaptogenesis. The second area utilizes a mouse mutant , nob, the gene for which we have recetly cloned to begin to identify the mechanism by which glutamate interaction with the mGLUR6 on bipolar cells modulates the cation channel responsible for signaling in the bipolar cells. The third area of interest utilizes the advantages of using zebrafish as a system to study retinal development. The laboratory collaborates with Dr. John Dowling at Harvard University and Dr. Brian Link at the Medical College of Wisconsin. Dr. Link identified several zebrafish mutants that have defects in normal lamination in the retina. These genes are involved in critical stages of neural cell determination and differentiation and the Gregg lab is using positional cloning to identify the underlying genes.