Dr. Jay D. Horton obtained his B.S. and M.D. degrees from the University of Iowa in 1984 and 1988, respectively. He completed his internal medicine residency (1988-1991) and gastroenterology fellowship (1991-1994) at UT Southwestern Medical Center. During his gastroenterology fellowship he studied metabolic regulators of bile acid and cholesterol homeostasis in animals. Following the gastroenterology fellowship, he completed a Howard Hughes post doctoral fellowship in the Department of Molecular Genetics at UT Southwestern Medical Center. The studies in this fellowship focused on the transcriptional regulation of cholesterol and fatty acid synthesis. In clinical digestive diseases, Dr. Horton has an interest in conditions that lead to steatosis and obesity. Currently the laboratory is investigating molecular mediators of steatosis using various mouse models. Investigations from the laboratory have revealed how the primary transcriptional regulators of cholesterol metabolism (sterol regulatory element-binding proteins) are also key regulators of fatty acid synthesis in liver. A major focus of the laboratory is to determine how these transcriptional regulators contribute to the development of steatosis in various disease processes such as diabetes, obesity, and beta-oxidation defects. A second area of investigation centers on determining the function of PCSK9, a protein that is involved in determining plasma LDL cholesterol levels through its ability to post-transcriptionally regulate the expression of the LDL receptor in liver.