For immediate release: April 9, 2007
Contact: Emily Wofford Cobb
Public Relations Manager
775-784-6006
ecobb@medicine.nevada.edu
Finding published in the Proceedings of the National Academy of Sciences
RENO, Nev.— Scientists at the University of Nevada School of Medicine have identified a gene that controls the shape of sperm. The gene is called Spem1 and loss of function of the gene in mice causes sperm deformation characterized by the sperm head bent back toward the sperm tail. The deformed sperm cannot fertilize eggs and thus results in male infertility. The scientists finding was published this week in the prestigious journal Proceedings of the National Academy of Sciences (PNAS).
“One out of every ten married couples at their reproductive ages in the United States experience infertility,” said Wei Yan, M.D., Ph.D., assistant professor of physiology and cell biology. “Male infertility account for about half of the fertility problems worldwide and about 45% of these cases have unknown causes. Identification of genes essential for normal sperm production represents the first step toward genetic diagnosis and future gene therapy for male infertility. Spem1 is one of the genes that we have identified to be indispensable for the production of normal sperm and male fertility.”
The research team, led by Yan, first identified Spem1 as a gene exclusively expressed in the testis. The team further inactivated the gene in mice using state-of-the-art gene knockout technology. Male mice lacking the Spem1 gene can produce normal numbers of sperm, but all sperm display bent heads in the neck region and a quick loss of motility. Researchers found the mutant mice with the Speml gene to be completely infertile.
“Humans and mice share 70% of the amino acids in the protein encoded by this gene,” said Huili Zheng, M.D., Ph.D., first author on the PNAS paper. “Therefore, it is likely that mutation of this gene in humans would lead to the same problem as seen in mice.”
Yan’s research group works on genes essential for sperm and egg production. These genes can be used for genetic screening and diagnosis of human infertility. Some of these genes and their encoded proteins can serve as excellent drug targets for the development of future non-hormonal contraceptives.
The research was funded by a start-up fund from the University of Nevada, Reno and research grants from the National Institute of Health. Other contributing authors include Clifford Stratton, Ph.D. and Jingling Jin, Ph.D. from the University of Nevada School of Medicine and Kazuto Morozumi, Ph.D. and Ryuzo Yanagimachi, Ph.D. from the John. A. Burns School of Medicine, University of Hawaii.
As the state’s only public medical school, the University of Nevada School of Medicine has been meeting statewide healthcare, educational, and clinical needs since 1969. The School of Medicine encompasses 16 clinical medical education departments, including Family Medicine, Pediatrics, Obstetrics/Gynecology, Internal Medicine, Surgery, and Psychiatry and Behavioral Sciences, as well as ten nationally-recognized departments within basic science including microbiology and biomedical engineering. As the largest multi-specialty healthcare focus within the state, the School of Medicine employs more than 185 doctors who both teach and practice medicine throughout Nevada. The school’s statewide faculty physician practice group has a combined 25 different medical specialties with seven physician practice offices located in the Reno-Sparks area and five physician offices located in Las Vegas.
The University of Nevada School of Medicine utilizes a best-practice approach to medicine and is committed to addressing the health needs of Nevada now and in the future. For more information, please visit www.medicine.nevada.edu .
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