Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


Researchers Uncover Fragile X Syndrome Gene’s Role in Shaping Brain

Researchers at UT Southwestern Medical Center have discovered how the genetic mutation that causes Fragile X syndrome, the most common form of inherited mental retardation, interferes with the “pruning” of nerve connections in the brain. Their findings appear in the April 29 issue of Neuron.

Soon after birth, the still-developing brain of a mammal produces too many nerve connections that create “noise” in the nervous system. The brain finds it hard to process these signals, like a person trying to have a conversation at a loud party. But as the brain matures and learning takes place, some nerve connections naturally become stronger while others weaken and die, leading to an adult with a properly wired brain.

Fragile X is caused by a mutation in a single gene, Fmr1, on the X chromosome. The gene codes for a protein called FMRP, which plays a role in learning and memory but whose full function is unknown. The protein’s role in pruning nerve connections had been unclear.

“I think we’ve uncovered a core function for the gene involved in this disease, and if we can find other biochemical methods involved in nerve pruning, we might be able to help correct this,” said Dr. Kimberly Huber, associate professor of neuroscience at UT Southwestern and senior author of the study.

In the current study, Dr. Huber and her colleagues examined nerve cells isolated from mice that had been engineered to lack the Fmr1 gene and, therefore, did not produce FMRP protein. They then tested whether the lack of FMRP affected the functions of another protein called MEF2, which is known to be involved in pruning nerve connections.

The researchers found that nerve cells lacking FMRP were unable to respond to MEF2. Adding FMRP to the cells restored MEF2’s normal function.

“We were massively activating the MEF2 gene in the cell, and it did absolutely nothing without FMRP,” Dr. Huber said. Such an all-or-nothing requirement in a biochemical relationship is rare, she said.

The findings also raise questions about how the two proteins interact physically. MEF2 works in the nucleus of a cell, where it controls whether other genes are turned on or off. FMRP shuttles in and out of the cell’s nucleus and into its main body.

“This opens up new ideas about how processes in the cell’s nucleus, near its DNA, can affect the nerve connections, which are very far away at the other end of the cell,” Dr. Huber said. “We think MEF2 is making messenger RNA [ribonucleic acid], which translates the genetic code of the DNA, and FMRP is binding to the RNA and either transporting it to the nerve connections and/or controlling how the RNA makes protein.”

Further research will focus on the relationship between the proteins. For instance, one might directly control the other, or they might work together on a common target, Dr. Huber said.

“This work might not have clinical implications for quite a while,” she said. “The goal for us as scientists is to understand how these genes relate to mechanisms that control the development of nerve connections.”

Like other genetic diseases carried on the X chromosome, Fragile X syndrome strikes boys more often and more severely than girls. Girls have two X chromosomes, so a normal gene on one chromosome can mitigate the effects of the disease if the gene on the other X chromosome is abnormal. Boys, however, have only one X chromosome, so if they inherit an abnormal gene on the X chromosome, they have no protection.

Other UT Southwestern researchers involved in the study were lead author and former graduate student Brad Pfeiffer; Dr. Tong Zang, postdoctoral researcher in neuroscience; Dr. Julia Wilkerson, postdoctoral researcher in neuroscience; Dr. Makoto Taniguchi, postdoctoral researcher in psychiatry; Marina Maksimova, research assistant in neuroscience; Dr. Laura Smith, postdoctoral researcher in psychiatry; and Dr. Christopher Cowan, assistant professor of psychiatry.

The study was funded by the National Institutes of Health, Autism Speaks, the Whitehall Foundation and Simons Foundation.

Aline McKenzie | Newswise Science News
Further information:

Further reports about: Brain DNA FMR1 Gene’s MEF2 RNA Syndrome Uncover X chromosome cell’s nucleus genetic disease nerve cell

More articles from Life Sciences:

nachricht Biologists unravel another mystery of what makes DNA go 'loopy'
16.03.2018 | Emory Health Sciences

nachricht Scientists map the portal to the cell's nucleus
16.03.2018 | Rockefeller University

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Locomotion control with photopigments

Researchers from Göttingen University discover additional function of opsins

Animal photoreceptors capture light with photopigments. Researchers from the University of Göttingen have now discovered that these photopigments fulfill an...

Im Focus: Surveying the Arctic: Tracking down carbon particles

Researchers embark on aerial campaign over Northeast Greenland

On 15 March, the AWI research aeroplane Polar 5 will depart for Greenland. Concentrating on the furthest northeast region of the island, an international team...

Im Focus: Unique Insights into the Antarctic Ice Shelf System

Data collected on ocean-ice interactions in the little-researched regions of the far south

The world’s second-largest ice shelf was the destination for a Polarstern expedition that ended in Punta Arenas, Chile on 14th March 2018. Oceanographers from...

Im Focus: ILA 2018: Laser alternative to hexavalent chromium coating

At the 2018 ILA Berlin Air Show from April 25–29, the Fraunhofer Institute for Laser Technology ILT is showcasing extreme high-speed Laser Material Deposition (EHLA): A video documents how for metal components that are highly loaded, EHLA has already proved itself as an alternative to hard chrome plating, which is now allowed only under special conditions.

When the EU restricted the use of hexavalent chromium compounds to special applications requiring authorization, the move prompted a rethink in the surface...

Im Focus: Radar for navigation support from autonomous flying drones

At the ILA Berlin, hall 4, booth 202, Fraunhofer FHR will present two radar sensors for navigation support of drones. The sensors are valuable components in the implementation of autonomous flying drones: they function as obstacle detectors to prevent collisions. Radar sensors also operate reliably in restricted visibility, e.g. in foggy or dusty conditions. Due to their ability to measure distances with high precision, the radar sensors can also be used as altimeters when other sources of information such as barometers or GPS are not available or cannot operate optimally.

Drones play an increasingly important role in the area of logistics and services. Well-known logistic companies place great hope in these compact, aerial...

All Focus news of the innovation-report >>>



Industry & Economy
Event News

Ultrafast Wireless and Chip Design at the DATE Conference in Dresden

16.03.2018 | Event News

International Tinnitus Conference of the Tinnitus Research Initiative in Regensburg

13.03.2018 | Event News

International Virtual Reality Conference “IEEE VR 2018” comes to Reutlingen, Germany

08.03.2018 | Event News

Latest News

Wandering greenhouse gas

16.03.2018 | Earth Sciences

'Frequency combs' ID chemicals within the mid-infrared spectral region

16.03.2018 | Physics and Astronomy

Biologists unravel another mystery of what makes DNA go 'loopy'

16.03.2018 | Life Sciences

Science & Research
Overview of more VideoLinks >>>