Leland H. Hartwell

Leland H. Hartwell, born in 1939, American geneticist and cowinner of the 2001 Nobel Prize in physiology or medicine for discoveries about key regulators of cell division. Hartwell shared the prize with two British scientists, R. Timothy Hunt and Paul M. Nurse, from the Imperial Cancer Research Fund.

Leland Harrison Hartwell was born in Los Angeles, California. He showed an early interest in science, an interest fostered by a counselor at Glendale Junior College who steered him to the California Institute of Technology. After a year at Glendale, Hartwell transferred and received a B.S. degree from Caltech in 1961. A Ph.D. degree from the Massachusetts Institute of Technology followed in 1964. Having decided to focus his research efforts on cancer and cell division, Hartwell spent a postdoctoral year at the Salk Institute for Biological Studies in La Jolla, California, working with future Nobelist Renato Dulbecco. Hartwell taught at the University of California, Irvine, from 1965 to 1968, when he joined the faculty of the University of Washington. He became American Cancer Society Research Professor in the university’s department of genetics in 1990. While retaining his university position, he joined the faculty of the Fred Hutchinson Cancer Research Center in Seattle in 1996 and became president and director of the center in 1997.

Hartwell carried out his research on yeast cells, focusing on the cell cycle—the processes by which the cell replicates its genetic material and divides—and especially on the molecules that control these processes. Through this research he discovered more than 100 genes known as cell division cycle (CDC) genes, including CDC28, a gene that initiates the process and was dubbed “start.” Hartwell also introduced the notion of “checkpoints” during which the cell cycle stops so the cell can repair DNA errors that result during replication. The cell cycle is fundamental to all life forms, and its processes are regulated in human beings by genes that correspond to the yeast genes. Hartwell’s discoveries about the mechanisms that regulate the cell cycle advanced scientific understanding of cancer, a disease that involves unregulated cell division. Hartwell and Nurse, who also worked on the genetics of cell division in yeast, shared the Albert Lasker Basic Medicine Research Award in 1998 in recognition of their groundbreaking work on the cell cycle.