Fred Hutchinson Cancer Research Center, Seattle,
Leland Hartwell used
baker's yeast, Saccharomyces cerevisiae, as a
model system for genetic studies of the cell cycle.
In an elegant series of experiments 1970-71, he
isolated yeast cells, in which genes controlling the
cell cycle were altered (mutated). By this approach,
he identified genes specifically involved in cell
cycle control, so called CDC-genes (cell division
cycle genes). One of these genes, designated
CDC28, controls the first step in the
progression through the G1-phase of the cell cycle
(the function "start"). Hartwell also identified the
fundamental role of "checkpoints" in cell cycle
control. These checkpoints monitor that all steps in
the previous phase have been correctly executed and
ensure a correct order between the cell cycle
Important model organisms for this year's Laureates.
Leland Hartwell used baker's yeast, Saccharomyces
cerevisiae (left). Paul Nurse used another type
of yeast, Schizosaccharomyces pombe (middle).
Tim Hunt used sea urchin, Arbacia