Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Missing protein in Fragile X Syndrome is key to transporting signals within neurons

10.06.2008
Fragile X syndrome (FXS) robs the brain of a protein that plays a major role in the way neurons communicate and that is essential for brain development, learning and memory.

A team of scientists has discovered new information about how FXS interferes with signaling between the nucleus of neurons and the synapse, the outer reaches of the neuron where two neurons communicate via chemical and electrical signals. The discovery should help lead the way to the development of new treatments for FXS, the most common form of inherited mental retardation and also a genetic contributor to some types of autism and epilepsy.

The research will be published in the June 10 issue of Developmental Cell. The team was led by Gary J. Bassell, professor of cell biology and neurology at Emory University School of Medicine and Robert H. Singer, PhD, professor of anatomy & structural biology at the Albert Einstein College of Medicine. First author was Jason B. Dictenberg of Hunter College, City University of New York and Albert Einstein College of Medicine.

Translation of an organism's genetic information begins in the nucleus of a cell, where the DNA sequence (gene) is copied into an mRNA molecule, then exported into the cell's cytoplasm and translated into protein molecules.

... more about:
»FMRP »FXS »Neuron »Nucleus »Protein »RNA »Synapse »dendrites »mRNA

FXS is caused by the silencing of a single gene, which normally would encode for the expression of the fragile x mental retardation protein (FMRP)--an mRNA (messenger RNA) binding protein. mRNA binding proteins are known to be key regulators of gene expression because they act as master regulators of other mRNAs and broadly influence how proteins are synthesized from mRNAs.

The precise functions for FMRP have been unclear, but scientists recently have learned that FMRP is able to bind and regulate several mRNAs that are present at synapses in the brain. Each mRNA molecule can be translated many times at the synapse, producing many copies of the encoded protein and providing an efficient way for a neuron to supply its synapse with essential proteins needed for communication. Since mRNAs can be turned on or off, each synapse can decide for itself whether or not new proteins are needed to promote signaling. Proper signaling at synapses is essential for the complex wiring of connections that must occur during brain development and during learning and memory. In FXS, there are defects in both the structure and signaling at synapses, due to the lack of FMRP regulation of mRNAs at synapses. Until now, a major unanswered question has been how FMRP and its bound mRNAs are delivered to axons and dendrites Ð the tentacle-like projections of neurons-- and to the synapses at their outer extremities.

"A major challenge for the field of neuroscience has been to understand how a selective group of mRNAs can be transported long distances from the nucleus, where the RNA is made, to reach the synapses, where this select group of mRNAs can be translated into the protein molecules that are needed to enable signaling," says Bassell. "This mechanism of mRNA transport into axons and dendrites and its translation at synapses is critical for synapse signaling during learning, memory and cognition."

Bassell and his Emory colleagues have developed high resolution microscopic imaging tools to visualize FMRP in live neurons, allowing them to track the movements of FMRP and associated mRNA molecules along dendrites, using cultured neurons isolated from the hippocampus of mouse embryos.

The researchers discovered that FMRP binds to a molecular motor, which allows it to carry its bound mRNAs in the form of particles out into the dendrites.

"FMRP seems to be quite a clever protein that acts like a postal carrier to deliver messages to the synapse, enabling and sustaining their continued signaling," says Bassell.

In a mouse model of FXS, the investigators discovered that mRNAs are not motored into dendrites in response to synaptic signaling and thus cannot allow for local protein synthesis at synapses needed to sustain the synaptic signaling between nerve cells. In essence, the ability of the nerve cell to communicate from the nucleus to the synapse is lost in fragile X.

The researchers also were able to identify the select group of mRNAs that the neuron ships into dendrites via FMRP. Knowing which molecules within the FMRP pathway function at synapses should facilitate the development of new treatment strategies and drug interventions for FXS.

Holly Korschun | EurekAlert!
Further information:
http://www.emory.edu

Further reports about: FMRP FXS Neuron Nucleus Protein RNA Synapse dendrites mRNA

More articles from Life Sciences:

nachricht Study shines light on brain cells that coordinate movement
26.06.2017 | University of Washington Health Sciences/UW Medicine

nachricht New insight into a central biological dogma on ion transport
26.06.2017 | Aarhus 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: Can we see monkeys from space? Emerging technologies to map biodiversity

An international team of scientists has proposed a new multi-disciplinary approach in which an array of new technologies will allow us to map biodiversity and the risks that wildlife is facing at the scale of whole landscapes. The findings are published in Nature Ecology and Evolution. This international research is led by the Kunming Institute of Zoology from China, University of East Anglia, University of Leicester and the Leibniz Institute for Zoo and Wildlife Research.

Using a combination of satellite and ground data, the team proposes that it is now possible to map biodiversity with an accuracy that has not been previously...

Im Focus: Climate satellite: Tracking methane with robust laser technology

Heatwaves in the Arctic, longer periods of vegetation in Europe, severe floods in West Africa – starting in 2021, scientists want to explore the emissions of the greenhouse gas methane with the German-French satellite MERLIN. This is made possible by a new robust laser system of the Fraunhofer Institute for Laser Technology ILT in Aachen, which achieves unprecedented measurement accuracy.

Methane is primarily the result of the decomposition of organic matter. The gas has a 25 times greater warming potential than carbon dioxide, but is not as...

Im Focus: How protons move through a fuel cell

Hydrogen is regarded as the energy source of the future: It is produced with solar power and can be used to generate heat and electricity in fuel cells. Empa researchers have now succeeded in decoding the movement of hydrogen ions in crystals – a key step towards more efficient energy conversion in the hydrogen industry of tomorrow.

As charge carriers, electrons and ions play the leading role in electrochemical energy storage devices and converters such as batteries and fuel cells. Proton...

Im Focus: A unique data centre for cosmological simulations

Scientists from the Excellence Cluster Universe at the Ludwig-Maximilians-Universität Munich have establised "Cosmowebportal", a unique data centre for cosmological simulations located at the Leibniz Supercomputing Centre (LRZ) of the Bavarian Academy of Sciences. The complete results of a series of large hydrodynamical cosmological simulations are available, with data volumes typically exceeding several hundred terabytes. Scientists worldwide can interactively explore these complex simulations via a web interface and directly access the results.

With current telescopes, scientists can observe our Universe’s galaxies and galaxy clusters and their distribution along an invisible cosmic web. From the...

Im Focus: Scientists develop molecular thermometer for contactless measurement using infrared light

Temperature measurements possible even on the smallest scale / Molecular ruby for use in material sciences, biology, and medicine

Chemists at Johannes Gutenberg University Mainz (JGU) in cooperation with researchers of the German Federal Institute for Materials Research and Testing (BAM)...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Plants are networkers

19.06.2017 | Event News

Digital Survival Training for Executives

13.06.2017 | Event News

Global Learning Council Summit 2017

13.06.2017 | Event News

 
Latest News

Study shines light on brain cells that coordinate movement

26.06.2017 | Life Sciences

Smooth propagation of spin waves using gold

26.06.2017 | Physics and Astronomy

Switchable DNA mini-machines store information

26.06.2017 | Information Technology

VideoLinks
B2B-VideoLinks
More VideoLinks >>>