SIR DR. TIM HUNT
Tim Hunt grew up in Oxford, where he became fascinated by science at the Dragon School. At 14, he entered Magdalen College School, where his interest in biology grew. Tim entered Clare College, Cambridge in 1961 to read Natural Sciences. He joined the Department of Biochemistry in 1964 as a graduate student working on the control of haemoglobin synthesis. In 1968 he moved to the Albert Einstein College of Medicine in New York as a postdoctoral Fellow with Irving London.
Tim returned to the Department of Biochemistry in Cambridge in 1971 where he continued to work on translational control throughout the 1970s. He taught summer courses at the Marine Biological Laboratory, Woods Hole, Massachusetts from 1977 to 1983, looking at changes in protein synthesis in sea urchin and clam eggs after fertilisation. In 1979, he helped Joan Ruderman and Eric Rosenthal with experiments on the translational control of maternal mRNA in clam eggs, where two of the major mRNAs concerned later turned out to be the A and B-type cyclins.
By 1982, Tim had almost exhausted the potential of sea urchin eggs, but it was then that he performed the experiment that led to the discovery of cyclins and subsequent research on the control of the cell cycle. In 1990, Tim joined ICRF (now The Francis Crick Institute) in London. He became a fellow of the Royal Society in 1991, a foreign associate of the US National Academy of Sciences in 1999 and shared the Nobel Prize for Physiology or Medicine with Lee Hartwell and Paul Nurse in 2001. He enjoys cooking, photography and making up problems for Molecular Biology of the Cell with his friend John Wilson. In 2016, he and his wife Mary Collins moved to Okinawa, where Mary was the Provost of OIST (Okinawa Institute of Science and Technology). In 2022, Mary was appointed Director of the Blizard Institute of QMUL and they returned to London.
One of the most amazing things about living organisms is that they tend to stay the same. I think of noses, for example. Your nose neither shrinks nor grows (once you’ve grown up), yet it’s a completely new nose every 7 years or so. Not a single molecule remains after some time, thanks to continual turnover. Remarkable. Closer to home as far as my research career went is the case of red blood cells. It’s very important to keep the number of red cells in your blood within certain limits. Too few, and oxygen will be in short supply to your brain. Too many, and blood gets so thick it cannot circulate any more. The number of red cells is controlled by feedback circuits that measure oxygen in the kidney and regulate the production of the hormone erythropoietin.
Inside the red cells there are also feedback controls, to ensure a balanced supply of the components of haemoglobin, which are (I found this very funny when I first heard it) haem and globin. If you starve young red cells of iron, they cannot make haem and globin synthesis stops. If you inhibit globin synthesis, haem synthesis stops. For ten years I worked on the problem of how haem controlled globin synthesis, finally discovering the biochemical mechanism in about 1975. It was a very tangled path, which I’ll try to sketch briefly.
Having solved this problem, I needed something new to study, and turned to sea urchin eggs, which start making new proteins after fertilization. How does that work? In the course of these studies, which were done during summer holidays in America, I alss got interested in clam eggs, which start making new proteins after fertilization. But why (as well as how)? Then one day, when things were getting rather desperate, because progress had been so slow and we’d run out of ideas, I did a very simple experiment and discovered to my surprise that one or two of the most strongly synthesized new proteins disappeared, just before the eggs divided for the first time. This was impossible, or so people thought at the time, but I saw it clearly and reproducibly. And the proteins came back again and disappeared again every time the cells divided. Moreover, if you stopped them coming back, the cells stopped dividing. It looked like these proteins were essential catalysts of cell division that had to be destroyed to complete the division cycle of events. It took five or six years to find out what was going on. There are some important lessons about how cells change their state—in this case, from Interphase to Mitosis—and how they complete mitosis and return to interphase. I hope I will be able to explain.
