Genetics and Cell Biology

Yeast raises understanding of human biochemistry

Some are our allies, helping us make bread and beer. Others are enemies, invading our bodies. Friend or foe, yeast are highly valued by CBS scientists who use them to explore fundamental biochemical processes.

Yeast researchers (clockwise) Deanna Koepp, Duncan Clarke, David Kirkpatrick, Robin Wright (Associate Dean) and Judy Berman. All are faculty in the Department of Genetics, Cell Biology, and Development.

"You can do really sophisticated genetic experiments with yeast that you really can't do with other organisms," says Deanna Koepp. An assistant professor in the Department of Genetics, Cell Biology, and Development (GCD), Koepp is studying the biochemical regulation of cell division. "Basically, a single cell of yeast does the same sorts of things a single human cell does," she says, making her experiments 'completely applicable' to hot topics such as cancer prevention.

Some of the laboratories studying yeast are focusing on Candida albicans, which infects and sometimes kills humans. GCD professor Pete Magee is mapping the organism's genome and studying how it gains genetic variability. Cheryl Gale of GCD and the Department of Pediatrics, Dana Davis of the Department of Microbiology, and Judith Berman, professor of GCD, are studying other aspects of C. albicansin hopes of reducing its impact on humans.

Most of the yeast researchers here, however, work with Saccharomyces cerevisiae, the yeast used in bread-baking and beer-making. S. cerevisiae's genome was sequenced in 1996, making it possible for researchers to "very quickly home in on genes that might be interesting," says Duncan Clarke, assistant professor of GCD.

For Clarke that means genes that control chromosomes during cell division, as well as those that keep cells from dividing before their genes are replicated--a control that's at the crux of much that goes awry in cancers and mutations. For colleague Anja Bielinsky, assistant professor in the Department of Biochemistry, Molecular Biology, and Biophysics (BMBB), the genes of interest are those that regulate replication. Robin Wright, associate dean, focuses on synthesis of endoplasmic reticulum, which plays a role in making proteins and degrading poisons. BMBB professor Dennis Livingston is looking at how cells repair damaged DNA.

"All of us are addressing specific problems in cell biology and cell metabolism using a large variety of methods," says GCD assistant professor David Kirkpatrick. "They are all different aspects of the basic way a cell grows and lives."

Yeast researchers have benefited tremendously from the opening last year of the Molecular and Cellular Biology Building on the Minneapolis campus. Seven yeast labs are all housed on one floor.

"It's really nice," says BMBB associate professor Paul Siliciano, who is studying how cells dispose of noncoding portions of DNA during the gene-to-protein translation process. "We have a lot more collisions with each other... We talk, also, about things we otherwise wouldn't talk about."

Kirkpatrick says the setting has done much to encourage collaboration. He and Magee recently submitted a proposal for a project that will bring his basic research on DNA repair in S. cerevisiaeto bear on Magee's C. albicans work--with potentially profound implications for foiling the virulent species ability to develop resistance to antifungal agents. "That never would have happened if he hadn't been two doors down from me," Kirkpatrick says.

Mary K. Hoff