Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

2 new genes linked to amyotrophic lateral sclerosis and related disorders

04.03.2013
St. Jude Children's Research Hospital ties mutations in 2 genes to the death of motor neurons associated with ALS, or Lou Gehrig's disease, and other devastating neurodegenerative problems

A study led by St. Jude Children's Research Hospital has discovered mutations in two genes that lead to the death of nerve cells in amyotrophic lateral sclerosis (ALS), also known as Lou Gehrig's disease, and related degenerative diseases.

The same mutation occurred in both genes and led to the abnormal build-up of the proteins inside cells. These proteins play an essential role in normal RNA functioning and have also been linked to cancer, including the Ewing sarcoma, the second most common type of bone cancer in children and adolescents. The finding is the latest in a series of discoveries suggesting degenerative diseases and cancer may have common origins. RNA is the molecule that directs protein assembly based on instructions carried in DNA.

The study also adds to evidence that seemingly unrelated neurodegenerative diseases may involve similar defects in RNA metabolism. Researchers linked the problems to a specific region of the mutated proteins whose normal function was unclear. The study was published today in the advanced online edition of the scientific journal Nature.

"I hope this study helps to build the foundation for desperately needed treatments for ALS and perhaps a broad range of diseases caused by abnormal RNA metabolism," said J. Paul Taylor, M.D., Ph.D., an associate member of the St. Jude Department of Developmental Neurobiology and senior author of the study. Taylor and James Shorter, Ph.D., an assistant professor in the biochemistry and biophysics department at the University of Pennsylvania's Perelman School of Medicine, are the study's corresponding authors.

Each year approximately 5,600 people in the U.S. are found to have ALS. The disease is nearly always fatal, often within five years. Patients suffer muscle wasting and paralysis that affects their limbs and trunk as well as their ability to talk, swallow and breathe. There is no cure.

For this project, St. Jude sequenced just the portion of the genome called the exome, which carries instructions for making proteins. Researchers sequenced the exomes of two families affected by rare inherited degenerative disorders that target cells in the muscle, bone and brain. Neither family carried mutations previously tied to ALS or related diseases. The project built on the infrastructure developed by the St. Jude Children's Research Hospital -- Washington University Pediatric Cancer Genome Project, which played an important role in finding the mutations.

Researchers found the families carried a single, previously unknown mutation in a pair of RNA-binding proteins named hnRNPA2B1 and hnRNPA1. The proteins both bind RNA and help regulate its function. When researchers checked for the same mutations in 517 ALS patients they found hnRNPA1 protein mutated in two patients. One patient had the inherited form of ALS. The other ALS patient had no family history of the disease.

The new mutations occurred in a region of the proteins Taylor refers to as a prion-like domain because it has similarities with yeast proteins called prions. Prions are proteins that can alternate between shapes as needed for different functions. "Until recently we did not know these domains existed in humans and now we realize that hundreds of human proteins have them," Taylor said. "We're only beginning to understand their function in human cells."

Researchers showed the prion-like domains are responsible for the shape change that occurs when these proteins convert into slender threads called fibrils. The mutations accelerate fibril formation and recruit normal proteins to form fibrils. This phenomenon called propagation may explain how ALS and related diseases spread throughout the nervous system.

Taylor speculated that the normal function of prion-like domains is to assemble RNAs into temporary structures called granules, which are part of the cell's normal protein production machinery. Granules are normally short lived, and the RNA-binding proteins involved in their formation are recycled. But in cells with hnRNPA2B1 or hnRNPA1 mutation, RNA granules accumulated in the cytoplasm instead of being disassembled. "That's bad news for RNA regulation, which is bad news for those cells," Taylor said.

The study has several important implications, Taylor said. Recognition that the mutations adversely impact regulation of RNA could lead to targeted therapy to correct the problem. The mutation's location in the prion-like domain might also prove significant. Although the mutations in hnRNPA2B1 or hnRNPA1 appear to be rare, hundreds of other RNA-binding proteins have prion-like domains. Taylor said patients with unexplained neurodegenerative diseases may have mutations in these proteins.

The study's first authors are Hong Joo Kim, Nam Chul Kim, Yong-Dong Wang and Jennifer Moore, all of St. Jude; and Emily Scarborough and Zamia Diaz, both of the University of Pennsylvania. The other authors are Kyle MacLea and Eric Ross, both of Colorado State University; Brian Freibaum, Songqing Li, Anderson Kanagaraj and Robert Carter, all of St. Jude; Amandine Molliex, formerly of St. Jude; Kevin Boylan, Aleksandra Wojtas and Rosa Rademakers, all of the Mayo Clinic, Jacksonville, Fla.; Jack Pinkus and Steven Greenberg, both of Brigham and Women's Hospital and Harvard Medical School; John Trojanowski, Bradley Smith, Yun Li and Alice Flynn Ford, all of the University of Pennsylvania; Bryan Traynor, of the National Institute of Aging, National Institutes of Health, Bethesda, Md.; Simon Topp, Athina-Soragia Gkazi, Jack Miller and Christopher Shaw, all of the Institute of Psychiatry, London; Michael Kottlors and Janbernd Kirschner, both of University Children's Hospital Freiburg, Germany; Alan Pestronk and Conrad Weihl, both of the Washington University School of Medicine, St. Louis; Aaron Gitler, Stanford University School of Medicine; Michael Benatar, University of Miami Miller School of Medicine; Oliver King, Boston Biomedical Research Institute, Watertown, Mass.; and Virginia Kimonis, University of California-Irvine.

The research was supported in part by the Packard Foundation, by grants (NS053825, AG032953, DP2OD002177 and NS067354) from the National Institutes of Health, the ALS Association, the Ellison Medical Foundation, a grant (MCB-1023771) from the National Science Foundation and ALSAC.

St. Jude Children's Research Hospital

St. Jude Children's Research Hospital is internationally recognized for its pioneering research and treatment of children with cancer and other life-threatening diseases. The hospital's research has helped push overall survival rates for childhood cancer from less than 20 percent when the institution opened to almost 80 percent today. It is the first and only National Cancer Institute-designated Comprehensive Cancer Center devoted solely to children, and no family ever pays St. Jude for anything. For more information, visit www.stjude.org. Follow us on Twitter @StJudeResearch.

Summer Freeman | EurekAlert!
Further information:
http://www.stjude.org

More articles from Life Sciences:

nachricht Newly discovered bacteria-binding protein in the intestine
08.12.2016 | University of Gothenburg

nachricht The balancing act: An enzyme that links endocytosis to membrane recycling
07.12.2016 | National Centre for Biological Sciences

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Significantly more productivity in USP lasers

In recent years, lasers with ultrashort pulses (USP) down to the femtosecond range have become established on an industrial scale. They could advance some applications with the much-lauded “cold ablation” – if that meant they would then achieve more throughput. A new generation of process engineering that will address this issue in particular will be discussed at the “4th UKP Workshop – Ultrafast Laser Technology” in April 2017.

Even back in the 1990s, scientists were comparing materials processing with nanosecond, picosecond and femtosesecond pulses. The result was surprising:...

Im Focus: Shape matters when light meets atom

Mapping the interaction of a single atom with a single photon may inform design of quantum devices

Have you ever wondered how you see the world? Vision is about photons of light, which are packets of energy, interacting with the atoms or molecules in what...

Im Focus: Novel silicon etching technique crafts 3-D gradient refractive index micro-optics

A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.

Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...

Im Focus: Quantum Particles Form Droplets

In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.

“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...

Im Focus: MADMAX: Max Planck Institute for Physics takes up axion research

The Max Planck Institute for Physics (MPP) is opening up a new research field. A workshop from November 21 - 22, 2016 will mark the start of activities for an innovative axion experiment. Axions are still only purely hypothetical particles. Their detection could solve two fundamental problems in particle physics: What dark matter consists of and why it has not yet been possible to directly observe a CP violation for the strong interaction.

The “MADMAX” project is the MPP’s commitment to axion research. Axions are so far only a theoretical prediction and are difficult to detect: on the one hand,...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ICTM Conference 2017: Production technology for turbomachine manufacturing of the future

16.11.2016 | Event News

Innovation Day Laser Technology – Laser Additive Manufacturing

01.11.2016 | Event News

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

14.10.2016 | Event News

 
Latest News

Scientists track chemical and structural evolution of catalytic nanoparticles in 3-D

08.12.2016 | Materials Sciences

Decoding cement's shape promises greener concrete

08.12.2016 | Materials Sciences

Will Earth still exist 5 billion years from now?

08.12.2016 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>