"The prize recognizes the confluence of two different approaches to learning about the molecular machinery regulating the cell cycle," says Ira Herskowitz, professor in the department of biochemistry and biophysics at the University of California, San Francisco. The story of this convergence starts with Hartwell, a man whose discoveries rival baked bread, beer, and wine as yeast's greatest contribution to mankind. While screening for temperature-sensitive mutants in the yeast Saccharomyces cerevisiae in the 1960s and '70s, Hartwell identified a slew of genes that, in mutant form, arrest mitosis.
From this and other discoveries, including the discovery of the RAD9 gene with former postdoc Ted Weinert, Hartwell hypothesized that checkpoints regulate the sequence of events in mitosis.1 His seminal 1989 review paper made a number of cell cycle checkpoint predictions, including the cell cycle checkpoint role in ataxia- telangiectasia. "I was not surprised," says Weinert, now at the University of Arizona. ...
