CHARGE, which affects 1 in 10,000 babies, is an acronym whose letters stand for some of the more common symptoms of the condition: coloboma of the eye, heart defects, atresia of the choanae, retardation of growth and/or development, genital and/or urinary abnormalities, and ear abnormalities and deafness.
Originally, the researchers were examining the tumor-suppressive properties of the protein, called p53, not investigating developmental disorders. But when a mouse model developed a strange set of deficiencies, the researchers followed a trail of clues that led them to link p53 with CHARGE syndrome.
"It was a very big surprise and very intriguing," said Jeanine Van Nostrand, PhD, lead author of a paper describing the research and a former Stanford graduate student, now at The Salk Institute for Biological Studies. "P53 had never before been shown to have a role in CHARGE."
The paper will be published online Aug. 3 in Nature. The senior author is Laura Attardi, PhD, professor of radiation oncology and of genetics.
Cellular quality control regulator
The researchers originally created a mouse model that expressed a mutated form of the protein, known as p53, to investigate the behavior of p53 in suppressing tumors. Mice expressing only the mutated protein survived. But to their surprise, heterozygous mice, or those with one copy of the mutated p53 and one normal copy, developed symptoms of CHARGE and died in utero.
P53 is a cellular quality-control regulator. When it spots an ailing cell, it triggers other proteins to kill the cell or arrest its division. In a developing human or mouse, other proteins switch off p53 so it doesn't inadvertently kill important cells. The mutated form of p53 created by the researchers had a disabled off-switch, but it also couldn't communicate with other proteins to spark the cellular death. Therefore, a mouse containing only the mutated p53 survived to adulthood.
But when mice had one copy of a mutated p53 gene and one normal copy, the resultant proteins formed hybrids. These hybrid p53 proteins couldn't be turned off, but they retained the ability to trigger cellular death. Interestingly, these proteins only affected certain types of cells, causing the symptoms of CHARGE. The results suggest that p53 may play a role in other developmental disorders, Attardi said.
"It really reiterates how carefully p53 must be regulated," Attardi said. "It needs to be turned on at the right time and place. If it's not, it can cause damage."
CHARGE linked to gene mutation
The mechanisms of CHARGE syndrome remain a mystery, although it has been linked to a mutation in a gene called CHD7. Attardi's team examined the connection between p53 and CHD7. They discovered that the CHD7 protein can keep p53 turned off.
By linking p53 with CHARGE, this study elucidates molecular pathways that could be used to develop CHARGE therapies, said co-author Donna Martin, MD, PhD, associate professor of pediatrics and of human genetics at the University of Michigan Medical School and an expert on CHARGE.
Additional Stanford authors are former graduate students Colleen Brady, PhD, and Thomas Johnson, MD; postdoctoral scholar Heiyoun Jung, PhD; graduate students Daniel Fuentes, Chieh-Yu Lin and Chien-Jung Lin; Margaret Kozak, a former research assistant; Hannes Vogel, MD, professor of pathology and of pediatrics; Jonathan Bernstein, MD, assistant professor of pediatrics; and Joanna Wysocka, PhD, associate professor of chemical and systems biology and of developmental biology.
Other authors of the study are affiliated with Hôpital Necker-Enfants Malades in Paris, Université Paris Descartes, the Indiana University School of Medicine and the University of Michigan Medical School.
The study was supported by the National Science Foundation; the National Cancer Institute (grant 1F31CA167917); the National Institutes of Health (grants R01GM095555, R01DC009410, HL118087, HL121197 and R01CA140875); the American Heart Association; the March of Dimes Foundation; the American Cancer Society; and the Leukemia & Lymphoma Society.
Information about the Stanford's Department of Radiation Oncology and the Department of Genetics, which also supported the study, is available at http://radonc.stanford.edu and http://genetics.stanford.edu.
The Stanford University School of Medicine consistently ranks among the nation's top medical schools, integrating research, medical education, patient care and community service. For more news about the school, please visit http://mednews.stanford.edu. The medical school is part of Stanford Medicine, which includes Stanford Hospital & Clinics and Lucile Packard Children's Hospital Stanford. For information about all three, please visit http://stanfordmedicine.org/about/news.html.
Print media contact: Rosanne Spector at (650) 725-5374 (email@example.com)
Broadcast media contact: M.A. Malone at (650) 723-6912 (firstname.lastname@example.org)
Rosanne Spector | Eurek Alert!
The birth of a new protein
20.10.2017 | University of Arizona
Building New Moss Factories
20.10.2017 | Albert-Ludwigs-Universität Freiburg im Breisgau
University of Maryland researchers contribute to historic detection of gravitational waves and light created by event
On August 17, 2017, at 12:41:04 UTC, scientists made the first direct observation of a merger between two neutron stars--the dense, collapsed cores that remain...
Seven new papers describe the first-ever detection of light from a gravitational wave source. The event, caused by two neutron stars colliding and merging together, was dubbed GW170817 because it sent ripples through space-time that reached Earth on 2017 August 17. Around the world, hundreds of excited astronomers mobilized quickly and were able to observe the event using numerous telescopes, providing a wealth of new data.
Previous detections of gravitational waves have all involved the merger of two black holes, a feat that won the 2017 Nobel Prize in Physics earlier this month....
Material defects in end products can quickly result in failures in many areas of industry, and have a massive impact on the safe use of their products. This is why, in the field of quality assurance, intelligent, nondestructive sensor systems play a key role. They allow testing components and parts in a rapid and cost-efficient manner without destroying the actual product or changing its surface. Experts from the Fraunhofer IZFP in Saarbrücken will be presenting two exhibits at the Blechexpo in Stuttgart from 7–10 November 2017 that allow fast, reliable, and automated characterization of materials and detection of defects (Hall 5, Booth 5306).
When quality testing uses time-consuming destructive test methods, it can result in enormous costs due to damaging or destroying the products. And given that...
Using a new cooling technique MPQ scientists succeed at observing collisions in a dense beam of cold and slow dipolar molecules.
How do chemical reactions proceed at extremely low temperatures? The answer requires the investigation of molecular samples that are cold, dense, and slow at...
Scientists from the Max Planck Institute of Quantum Optics, using high precision laser spectroscopy of atomic hydrogen, confirm the surprisingly small value of the proton radius determined from muonic hydrogen.
It was one of the breakthroughs of the year 2010: Laser spectroscopy of muonic hydrogen resulted in a value for the proton charge radius that was significantly...
17.10.2017 | Event News
10.10.2017 | Event News
10.10.2017 | Event News
20.10.2017 | Information Technology
20.10.2017 | Materials Sciences
20.10.2017 | Interdisciplinary Research