Budding yeast in a UC San Francisco lab are yielding possible insight into a key step leading to the creation of human sperm. And the finding, say the UCSF researchers, could ultimately pave the way for an understanding of why human sperm sometimes doesn't fully develop, causing sterility.

In their study, published in the April issue of Molecular Cell, the UCSF researchers have identified the molecular steps that are involved in pushing a yeast spore, the equivalent of human sperm, through a critical stage of development. And they have determined that when these steps don't take place development is arrested--permanently.

Intriguingly, this finding may offer insight into the molecular glitch that causes a male infertility syndrome. Men with the infertility syndrome have immature sperm that are developmentally interrupted at the same stage of creation as was observed in defective yeast spores.

"This observation sets out a whole paradigm for exploring the human genetics of infertility in men," says Renee Reijo, a leading researcher on sperm-related infertility in men and a UCSF assistant professor of obstetrics-gynecology and reproductive sciences. "It is probably the most elegant model for examining the creation of sperm I've seen."

"If nothing else," says lead author Shelley Chu, a graduate student in the laboratory of Ira Herskowitz, PhD, professor of biochemistry and biophysics, and co-director of the Program in Human Genetics at UCSF, "this study provides a framework for understanding how sperm progress through this critical stage of development. Until now, we didn't have a clue about the molecular targets responsible for this transition." Chu is in the UCSF Program of Genetics and Cell Biology.

While yeast, single-celled fungi, are best known for their role in making beer brew and bread rise, their sp
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Contact: Jennifer O'Brien
jobrien@itsa.ucsf.edu
(415) 476-2557
University of California - San Francisco
23-Apr-1998