Featured Research

from universities, journals, and other organizations

Discovery Of Mutation May Lead To Help For Male Fertility Problems

Date:
November 24, 1998
Source:
University Of Texas Southwestern Medical Center At Dallas
Summary:
Discovery of a mutation that prevents sperm maturation could lead to treatments for male sterility and development of new male contraceptives, UT Southwestern Medical Center at Dallas scientists reported in today's issue of Proceedings of the National Academy of Sciences.

DALLAS - November 24, 1998 - Discovery of a mutation that prevents sperm maturation could lead to treatments for male sterility and development of new male contraceptives, UT Southwestern Medical Center at Dallas scientists reported in today's issue of Proceedings of the National Academy of Sciences.

Dubbed morc, or microrchidia, a medical term for abnormally small testes, the mutation in an unidentified gene is expressed only in males during the earliest stages of sperm production, said investigators from the labs of Dr. Mark Watson, assistant professor of pathology, and Dr. Andrew Zinn, assistant professor of internal medicine. The research mice, genetically engineered to have the mutation, are normal at birth and attempt to begin production of sperm at puberty. But their attempts fail, leading researchers to conclude that the morc gene performs a primary regulatory function in male meiosis, the process that produces sperm.

"This uncovers a new point in the regulation of sperm production," said Zinn, who is an investigator in the Eugene McDermott Center for Human Growth and Development. "A difference in this mutation compared with other mouse reproductive mutations is that it is selective for spermatogenesis (sperm production) and does not seem to affect oogenesis (egg formation in females).

The researchers began investigating the effects of this mutation when a former member of the team, Dr. Randall Moreadith, was experimenting to produce a mouse with certain genetic features. The first transgenic animal he made was sterile. The scientists launched an investigation to find out why these first rodents could not reproduce.

The researchers found no abnormalities in the mice except that they were infertile; the animals looked and behaved normally, including their mating instincts. Although they formed precursor cells for normal sperm production at birth, by about 10 days old -- puberty in a mouse -- the cells began dying. By the age of six months, all the sperm-producing cells were dead and the testicles were one-third normal size.

"Since a similar appearance is seen in some infertile men, these mice may provide a model for human sterility," Zinn said.

The researchers determined that the cells were dying at a very early stage of spermatogenesis through apoptosis, or programmed cell death. This is a natural process by which cells in the body, including sperm, are regulated for quantity and quality.

"But we don't know if the morc gene normally is involved in preventing apoptosis or whether the apoptosis is just a consequence of the germ cells not developing the way they normally would," Zinn said. "Because of the nature of this mutation, it should be relatively easy to clone the morc gene, which may reveal a new regulatory molecule involved in male reproduction. In fact, we have already identified a candidate gene.

"This is an important finding because, clinically, 10 percent of couples are faced with infertility. Once we know the pathway which the gene regulates, then biochemically, we may be able to manipulate it to either treat male sterility or to produce a new form of male birth control."

It also is possible that morc could be involved in testicular cancer. "One theory of human testicular tumors is that germ cells are blocked in sperm production," Zinn said. "This blockage during cell differentiation could cause them to become malignant, a mechanism that is common in leukemia and lymphoma."

The other researchers involved in the study were: Dr. Norimitsu Inoue, a postdoctoral fellow in the Eugene McDermott Center for Human Growth and Development; research assistants Karl Hess and George Albright; and Dr. Clark Duchene, a Southwestern Medical School graduate who is now an orthopaedic surgery resident at Parkland Health & Hospital System.

Funding from the UT Southwestern Program for Excellence in Research and the National Institutes of Health supported the research.


Story Source:

The above story is based on materials provided by University Of Texas Southwestern Medical Center At Dallas. Note: Materials may be edited for content and length.


Cite This Page:

University Of Texas Southwestern Medical Center At Dallas. "Discovery Of Mutation May Lead To Help For Male Fertility Problems." ScienceDaily. ScienceDaily, 24 November 1998. <www.sciencedaily.com/releases/1998/11/981124063527.htm>.
University Of Texas Southwestern Medical Center At Dallas. (1998, November 24). Discovery Of Mutation May Lead To Help For Male Fertility Problems. ScienceDaily. Retrieved July 30, 2014 from www.sciencedaily.com/releases/1998/11/981124063527.htm
University Of Texas Southwestern Medical Center At Dallas. "Discovery Of Mutation May Lead To Help For Male Fertility Problems." ScienceDaily. www.sciencedaily.com/releases/1998/11/981124063527.htm (accessed July 30, 2014).

Share This




More Health & Medicine News

Wednesday, July 30, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Generics Eat Into Pfizer's Sales

Generics Eat Into Pfizer's Sales

Reuters - Business Video Online (July 29, 2014) Pfizer, the world's largest drug maker, cut full-year revenue forecasts because generics could cut into sales of its anti-arthritis drug, Celebrex. Fred Katayama reports. Video provided by Reuters
Powered by NewsLook.com
Nigeria Ups Ebola Stakes on 1st Death

Nigeria Ups Ebola Stakes on 1st Death

Reuters - Business Video Online (July 29, 2014) Nigerian authorities have shut and quarantined a Lagos hospital where a Liberian man died of the Ebola virus, the first recorded case of the highly-infectious disease in Africa's most populous economy. David Pollard reports Video provided by Reuters
Powered by NewsLook.com
Running 5 Minutes A Day Might Add Years To Your Life

Running 5 Minutes A Day Might Add Years To Your Life

Newsy (July 29, 2014) According to a new study, just five minutes of running or jogging a day could add years to your life. Video provided by Newsy
Powered by NewsLook.com
Ebola Outbreak Poses Little Threat To U.S.: CDC

Ebola Outbreak Poses Little Threat To U.S.: CDC

Newsy (July 29, 2014) The Ebola outbreak in West Africa poses little threat to Americans, according to officials with the Centers for Disease Control and Prevention. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins