Tim Hunt

I describe myself as a molecular (cell) physiologist. While trying to understand how the oxygen carrier heme controlled the synthesis of its protein-binding partner, globin, I discovered that minute concentrations of double-stranded RNA, or low levels of oxidized glutathione, inhibited protein synthesis just like shortage of heme. Following these leads, I identified protein kinases that could switch off protein synthesis and allowed the development of highly active and well-understood extracts of young red blood cells ("reticulocytes") for assaying messenger RNA. Turning to different cells in which to study the control of protein synthesis, I discovered a protein in fertilized sea urchin eggs that was very suddenly and specifically degraded during cell division. Following this protein, which I called cyclin, led to studies of cell cycle control and cell cycle-regulated proteolysis. Most of the work in my laboratory now focuses on the meiotic and mitotic cell cycles of frog eggs.