): The overall objective of the proposed studies is to obtain information regarding the role of the bestrophin gene (VMD2) in retinal degeneration. Best Macular dystrophy (BMD, also called vitelliform macular dystrophy) is an autosomal dominant form of macular degeneration. BMD, caused by mutations in the VMD2 gene, leads to a progressive loss of central vision. Little is known about the protein product of this gene, called bestrophin. In the retina, bestrophin is specifically expressed in the plasma membrane of the retinal pigment epithelium (RPE). In the following application, I plan to conduct research toward understanding the physiological and molecular role of VMD2 in the retina. The first specific aim seeks to determine if mutations in the VMD2 gene cause other forms of retinal degeneration such as age-related macular degeneration (AMD) using PCR-based single-strand conformation polymorphism and direct genomic sequencing techniques. In the second aim, I plan to ascertain the subcellular localization of bestrophin in the plasma membrane of the RPE using imunocytochemistry. In the last aim, I propose in vitro electrophysiological studies as well as in vivo studies using mice. These studies include methods such as Ussing chambers, light, electron and fluorescent microscopy, gene transfer both in vivo and in vitro, electrocculography, and electroretinography. Discovering information regarding the function of bestrophin will hopefully provide knowledge about mechanisms involved in retinal degeneration.