Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


Gene defects could be new cause of male infertility

Scientists at the University of North Carolina at Chapel Hill have identified a gene crucial to the final step of the formation of a functional sperm cell.

That final step – called spermiogenesis – entails the compaction of DNA into a tight ball within the head of the sperm so it can successfully penetrate an egg.

Mice engineered to lack the crucial gene, Jhdm2a, that triggers this process did not produce many mature sperm, and those they did produce had abnormally shaped heads and immotile tails.

“Defects in this gene could be the cause for some cases of male infertility,” said study senior author Yi Zhang, Ph.D., Howard Hughes Medical Institute investigator and professor of biochemistry and biophysics in the UNC School of Medicine. Zhang is also a member of the UNC Lineberger Comprehensive Cancer Center.

... more about:
»DNA »Histone »Jhdm2a »cause »defect »infertility »sperm

“Because this gene has a very specific effect on the development of functional sperm, it holds great potential as a target for new infertility treatments that are unlikely to disrupt other functions within the body.”

The study, published on-line in the journal Nature Wednesday (Oct. 17, 2007), provides evidence that Jhdm2a directly controls expression of several genes required for DNA packaging in sperm cells. The research was funded by the Howard Hughes Medical Institute and the National Institutes of Health. For a sperm cell to mature fully, multiple molecular events have to occur, such as assembly of a sperm tail and packaging of sperm DNA.

In the sperm cell, yarn-like strands of DNA wrap around spools of protein called histones that package the DNA so it fits into the nucleus. Chemical tags such as methyl groups affixed to the histones govern how tightly the DNA can be packaged, affecting the accessibility for the gene to be switched on or off.

Previous studies have shown that when a gene is turned off, one of these histones, H3K9, carries a methyl tag. In a study published in Cell last year, Zhang’s laboratory demonstrated that the enzyme Jhdm2a removes this methyl tag, allowing the gene to become switched on, or expressed.

“Although a number of histone demethylases have been identified, very little is known regarding their biological functions, particularly in the context of whole animals,” said Yuki Okada, Ph.D., a postdoctoral fellow in Zhang’s laboratory and lead author on the study.

The unique expression pattern of Jhdm2a suggests that this demethylase may play an important role in the late stages of sperm cell development. In this study, mice genetically engineered to lack this gene had smaller testes, a significantly lower sperm count, and were infertile.

In addition, the few sperm that were produced by these mutant mice displayed significant morphological defects, including abnormally shaped heads and immotile tails.

To assess the packaging state of the sperm DNA, the researchers used electron microscopy and a fluorescent dye called acridine orange, which fluoresces differently depending on the packaging state of a sperm. Both techniques revealed a defect in sperm DNA packaging in the mutant mice, suggesting that incomplete DNA packaging was the cause of infertility.

“There are several mouse models that exhibit the male infertility seen in human syndromes such as azoospermia (absence of sperm) or globozoospermia (sperm with round heads),” said Zhang, “However, most of the genes required for normal spermatogenesis in mice are intact in human patients, raising the possibility that we might consider the jhdm2a gene as a culprit in these human male infertility syndromes.”

Zhang and his colleagues are now looking for mutations in this gene in infertility patients, and are also interested in identifying the partners or cofactors in the cell that help this gene do its job.

Les Lang | EurekAlert!
Further information:

Further reports about: DNA Histone Jhdm2a cause defect infertility sperm

More articles from Life Sciences:

nachricht Strong, steady forces at work during cell division
20.10.2016 | University of Massachusetts at Amherst

nachricht Disturbance wanted
20.10.2016 | Max Delbrück Center for Molecular Medicine in the Helmholtz Association

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: New 3-D wiring technique brings scalable quantum computers closer to reality

Researchers from the Institute for Quantum Computing (IQC) at the University of Waterloo led the development of a new extensible wiring technique capable of controlling superconducting quantum bits, representing a significant step towards to the realization of a scalable quantum computer.

"The quantum socket is a wiring method that uses three-dimensional wires based on spring-loaded pins to address individual qubits," said Jeremy Béjanin, a PhD...

Im Focus: Scientists develop a semiconductor nanocomposite material that moves in response to light

In a paper in Scientific Reports, a research team at Worcester Polytechnic Institute describes a novel light-activated phenomenon that could become the basis for applications as diverse as microscopic robotic grippers and more efficient solar cells.

A research team at Worcester Polytechnic Institute (WPI) has developed a revolutionary, light-activated semiconductor nanocomposite material that can be used...

Im Focus: Diamonds aren't forever: Sandia, Harvard team create first quantum computer bridge

By forcefully embedding two silicon atoms in a diamond matrix, Sandia researchers have demonstrated for the first time on a single chip all the components needed to create a quantum bridge to link quantum computers together.

"People have already built small quantum computers," says Sandia researcher Ryan Camacho. "Maybe the first useful one won't be a single giant quantum computer...

Im Focus: New Products - Highlights of COMPAMED 2016

COMPAMED has become the leading international marketplace for suppliers of medical manufacturing. The trade fair, which takes place every November and is co-located to MEDICA in Dusseldorf, has been steadily growing over the past years and shows that medical technology remains a rapidly growing market.

In 2016, the joint pavilion by the IVAM Microtechnology Network, the Product Market “High-tech for Medical Devices”, will be located in Hall 8a again and will...

Im Focus: Ultra-thin ferroelectric material for next-generation electronics

'Ferroelectric' materials can switch between different states of electrical polarization in response to an external electric field. This flexibility means they show promise for many applications, for example in electronic devices and computer memory. Current ferroelectric materials are highly valued for their thermal and chemical stability and rapid electro-mechanical responses, but creating a material that is scalable down to the tiny sizes needed for technologies like silicon-based semiconductors (Si-based CMOS) has proven challenging.

Now, Hiroshi Funakubo and co-workers at the Tokyo Institute of Technology, in collaboration with researchers across Japan, have conducted experiments to...

All Focus news of the innovation-report >>>



Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

Agricultural Trade Developments and Potentials in Central Asia and the South Caucasus

14.10.2016 | Event News

World Health Summit – Day Three: A Call to Action

12.10.2016 | Event News

Latest News

Innovative technique for shaping light could solve bandwidth crunch

20.10.2016 | Physics and Astronomy

Finding the lightest superdeformed triaxial atomic nucleus

20.10.2016 | Physics and Astronomy

NASA's MAVEN mission observes ups and downs of water escape from Mars

20.10.2016 | Physics and Astronomy

More VideoLinks >>>