Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Two genes -- Dax 1 and Sry -- required for testis formation

09.04.2003


The sex of newborns is dictated by the X and Y chromosomes – girls are XX whereas boys are XY. However, new research from Northwestern University has shown that normal testis formation depends on two genes -- the so-called male-determining SRY gene, found on the Y chromosome 10 years ago, and a gene called Dax1 on the X (female) chromosome.
Based on the findings of the Northwestern study, published in the May online Nature Genetics, it now appears that Dax1 is required at several points in embryonic testis development (http://dx.doi.org/10.108/Ng1141).

Until this study, Sry was the only known sex-determining gene. Dax1 had been widely accepted as an “anti-testis” or ovary-determining gene because patients with a duplication or “double dose” of Dax1 had features of XY sex reversal, a condition in which individuals have the chromosomes of males but the physical attributes of females.


Despite these findings, laboratory studies showed that deletion of the Dax1 gene in mice did not prevent ovarian development but instead revealed an important role in testis development.

Because most XY females do not have Sry mutations, Joshua J. Meeks, Jeffrey Weiss, and J. Larry Jameson, M.D., of the Feinberg School of Medicine at Northwestern University, hypothesized that other genes are necessary for testis determination.

Meeks, who is first author on the article, is an M.D./Ph.D. student at the Feinberg School. Weiss is research associate professor of medicine, and Jameson is Irving S. Cutter Professor and chair of medicine.

Their article described studies in XY sex-reversed mice lacking the Dax1 gene. Embryonic gonads were examined during the period when the bipotential gonad becomes a testis or an ovary.

Meeks and colleagues showed that the gonads of all of the Dax1-deleted XY sex-reversed mice had no testis cords -- a central feature of sex determination in males -- but had ovaries and external female genitalia and were anovulatory (sterile). Expression of the Sry gene was similar in Dax1-deleted mice and in those in which Dax1 was normal, indicating that sex reversal is not caused by reduced Sry levels in Dax1-deleted mice.

Further, Meeks said, “Sex reversal in the absence of Dax1 occurs subsequent to normal Sry expression, suggesting that Sry and Dax1 are both required for normal testis determination.” Meeks and colleagues at the Feinberg School have been studying the genetic mutations that cause sex reversal in an effort to reveal much-needed information about how these genes regulate gonad development and to better understand the causes of gonadal dysgenesis and infertility in humans.


This study was supported by a grant from the National Institutes of Health.


Elizabeth Crown | EurekAlert!
Further information:
http://www.nwu.edu/
http://dx.doi.org/10.108/Ng1141

More articles from Life Sciences:

nachricht NUI Galway highlights reproductive flexibility in hydractinia, a Galway bay jellyfish
24.02.2020 | National University of Ireland Galway

nachricht Shaping the rings of molecules
24.02.2020 | University of Montreal

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: A step towards controlling spin-dependent petahertz electronics by material defects

The operational speed of semiconductors in various electronic and optoelectronic devices is limited to several gigahertz (a billion oscillations per second). This constrains the upper limit of the operational speed of computing. Now researchers from the Max Planck Institute for the Structure and Dynamics of Matter in Hamburg, Germany, and the Indian Institute of Technology in Bombay have explained how these processes can be sped up through the use of light waves and defected solid materials.

Light waves perform several hundred trillion oscillations per second. Hence, it is natural to envision employing light oscillations to drive the electronic...

Im Focus: Freiburg researcher investigate the origins of surface texture

Most natural and artificial surfaces are rough: metals and even glasses that appear smooth to the naked eye can look like jagged mountain ranges under the microscope. There is currently no uniform theory about the origin of this roughness despite it being observed on all scales, from the atomic to the tectonic. Scientists suspect that the rough surface is formed by irreversible plastic deformation that occurs in many processes of mechanical machining of components such as milling.

Prof. Dr. Lars Pastewka from the Simulation group at the Department of Microsystems Engineering at the University of Freiburg and his team have simulated such...

Im Focus: Skyrmions like it hot: Spin structures are controllable even at high temperatures

Investigation of the temperature dependence of the skyrmion Hall effect reveals further insights into possible new data storage devices

The joint research project of Johannes Gutenberg University Mainz (JGU) and the Massachusetts Institute of Technology (MIT) that had previously demonstrated...

Im Focus: Making the internet more energy efficient through systemic optimization

Researchers at Chalmers University of Technology, Sweden, recently completed a 5-year research project looking at how to make fibre optic communications systems more energy efficient. Among their proposals are smart, error-correcting data chip circuits, which they refined to be 10 times less energy consumptive. The project has yielded several scientific articles, in publications including Nature Communications.

Streaming films and music, scrolling through social media, and using cloud-based storage services are everyday activities now.

Im Focus: New synthesis methods enhance 3D chemical space for drug discovery

After helping develop a new approach for organic synthesis -- carbon-hydrogen functionalization -- scientists at Emory University are now showing how this approach may apply to drug discovery. Nature Catalysis published their most recent work -- a streamlined process for making a three-dimensional scaffold of keen interest to the pharmaceutical industry.

"Our tools open up whole new chemical space for potential drug targets," says Huw Davies, Emory professor of organic chemistry and senior author of the paper.

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

70th Lindau Nobel Laureate Meeting: Around 70 Laureates set to meet with young scientists from approx. 100 countries

12.02.2020 | Event News

11th Advanced Battery Power Conference, March 24-25, 2020 in Münster/Germany

16.01.2020 | Event News

Laser Colloquium Hydrogen LKH2: fast and reliable fuel cell manufacturing

15.01.2020 | Event News

 
Latest News

NUI Galway highlights reproductive flexibility in hydractinia, a Galway bay jellyfish

24.02.2020 | Life Sciences

KIST researchers develop high-capacity EV battery materials that double driving range

24.02.2020 | Materials Sciences

How earthquakes deform gravity

24.02.2020 | Earth Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>