January 28, 2000 -- In an achievement that could lead to new techniques for genetic manipulation, Howard Hughes Medical Institute (HHMI) researchers at the University of Chicago have altered a protein to transmit a specific trait from one generation of yeast cell to another.

Their latest work builds on the discovery of a protein that transmits a genetic trait, a finding that hints at the presence of a menagerie of undiscovered protein-based "genetic elements" that may have driven evolution without the need for mutation of DNA genes.

Led by HHMI investigator Susan Lindquist at the University of Chicago, the researchers reported their findings in the January 28, 2000, issue of Science and in the January 2000 issue of Molecular Cell.

"Most people think of genetics as being only about DNA," said Lindquist. "But genetics is about the inheritance of traits. While most traits are inherited through transmission of DNA, the traits we study are inherited through proteins. Thus, these proteins can be every bit as much a genetic element as DNA. After all, they are heritable entities that span generations and influence a cell's phenotype in a predictable way."

In both studies, Lindquist's research team worked with yeast proteins known as "prions," which they and others had previously discovered could transmit different characteristics, called phenotypes, from one yeast generation to another.

Yeast prions are similar to mammalian prions that have gained notoriety for their roles in such fatal brain-destroying human diseases as Creutzfeldt-Jakob disease and kuru, and in the animal diseases, scrapie and bovine spongiform encephalopathy, or "mad cow disease."

Both yeast and mammalian prions transmit phenotypes via protein-protein interactions in which an abnormally shaped prion protein influences its normal counterpart to assume an abnorm
'"/>

Contact: Jim Keeley
keeleyj@hhmi.org
301-215-8858
Howard Hughes Medical Institute
27-Jan-2000