Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

A Surprising Pair of Proteins Help Make Healthy Eggs

17.02.2006


The biochemistry of fertility: A healthy egg, far left, is surrounded by normal, nurturing granulosa cells. Near left, an ovarian follicle lacking the TAF4b protein results in a misshapen egg and withered granulosa cells whose bonds are broken. Image: Richard Freiman, Brown University


Biologists at Brown University and the University of California–Berkeley have discovered that two proteins team up to turn on an assortment of ovarian genes critical to the production of healthy eggs. This finding, published in the Proceedings of the National Academy of Sciences, sheds important light on the biochemical processes underpinning fertility.

Human eggs rely on handmaidens. Called granulosa cells, they surround eggs and deliver nutrients and hormones. Without granulosa cells, eggs cannot mature and be successfully fertilized.

How do these handmaidens grow? Biologists at Brown University and the University of California–Berkeley have discovered that two proteins – TAF4b and c-Jun – team up to turn on about two dozen genes inside the nuclei of granulosa cells. This subset of genes, in turn, writes the genetic code for proteins that cause granulosa cells to multiply and nurture developing eggs.



The finding, published in an advanced online edition of the Proceedings of the National Academy of Sciences, provides an important piece of the reproduction puzzle, and it points to possible drug targets for treating infertility and ovarian cancer.

“Thousands of women in this country undergo fertility treatments each year and some have no idea why they can’t get pregnant,” said Richard Freiman, an assistant professor in the Department of Molecular Biology, Cell Biology and Biochemistry at Brown. “This research gives us important new information about fertility. It’s a basic science finding, but it may provide answers for some of these women and, possibly, lead to better in-vitro fertilization therapies.”

In 2001, Freiman and colleagues at Berkeley published a paper in Science describing the essential role a transcription factor called TAF4b plays in the fertility of female mice. Without this protein, egg-producing ovarian follicles didn’t develop properly. The result: infertile mice.

The new research underscores TAF4b’s central role in normal reproduction. The Brown and Berkeley team found that in the granulosa cells of the ovary, it triggers production of another protein, called c-Jun, and together they switch on a network of ovarian genes that help promote granulosa cell proliferation.

“The big surprise was c-Jun,” Freiman said.

That’s because this well-studied protein is found at high levels in damaged nerve tissue as well as in the tumors of certain cancers, including cancer of the skin and liver and in Hodgkin’s lymphoma. The new research is the first to connect c-Jun to this network of ovarian genes. Freiman said the discovery reveals a potential connection between TAF4b and c-Jun and the formation of a rare kind of ovarian cancer that springs from granulosa cells.

The scientists arrived at their findings by creating two matched rat cell lines of ovarian granulosa cell origin. In the experimental line, the level of TAF4b was increased. Berkeley researchers compared these lines and were able to identify the cooperative role of TAF4b and c-Jun, as well as the activation of the network of genes they control.

In parallel, Brown scientists studied the defective ovaries of TAF4b-deficient mice. What they found in mice was similar to what the Berkeley team found in cultured cells: When the level of TAF4b protein decreased, granulosa cells withered, broke apart and failed to multiply. A similar process may be at work in some infertile women.

Freiman plans to extend these studies to human granulosa tumors as well as explore a possible link between TAF4b and other forms of ovarian cancer, the fourth leading cause of cancer deaths among women.

Ekaterina Voronina, a Brown postdoctoral research fellow, assisted with the research. The Berkeley team included lead author Kenneth Geles, Wei-Li Liu and Shuang Zheng. Berkeley Professor Robert Tijan, an investigator with the Howard Hughes Medical Institute, oversaw the work.

The National Institutes of Health, the American Cancer Society, and the Howard Hughes Medical Institute funded the work.

Wendy Lawton | EurekAlert!
Further information:
http://www.brown.edu

More articles from Life Sciences:

nachricht Scientists uncover the role of a protein in production & survival of myelin-forming cells
19.07.2018 | Advanced Science Research Center, GC/CUNY

nachricht NYSCF researchers develop novel bioengineering technique for personalized bone grafts
18.07.2018 | New York Stem Cell Foundation

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: First evidence on the source of extragalactic particles

For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.

To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...

Im Focus: Magnetic vortices: Two independent magnetic skyrmion phases discovered in a single material

For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.

Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...

Im Focus: Breaking the bond: To take part or not?

Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.

A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...

Im Focus: New 2D Spectroscopy Methods

Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.

"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....

Im Focus: Chemical reactions in the light of ultrashort X-ray pulses from free-electron lasers

Ultra-short, high-intensity X-ray flashes open the door to the foundations of chemical reactions. Free-electron lasers generate these kinds of pulses, but there is a catch: the pulses vary in duration and energy. An international research team has now presented a solution: Using a ring of 16 detectors and a circularly polarized laser beam, they can determine both factors with attosecond accuracy.

Free-electron lasers (FELs) generate extremely short and intense X-ray flashes. Researchers can use these flashes to resolve structures with diameters on the...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Leading experts in Diabetes, Metabolism and Biomedical Engineering discuss Precision Medicine

13.07.2018 | Event News

Conference on Laser Polishing – LaP: Fine Tuning for Surfaces

12.07.2018 | Event News

11th European Wood-based Panel Symposium 2018: Meeting point for the wood-based materials industry

03.07.2018 | Event News

 
Latest News

Global study of world's beaches shows threat to protected areas

19.07.2018 | Earth Sciences

New creepy, crawly search and rescue robot developed at Ben-Gurion U

19.07.2018 | Power and Electrical Engineering

Metal too 'gummy' to cut? Draw on it with a Sharpie or glue stick, science says

19.07.2018 | Materials Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>