Navigation Links
How mitochondrial DNA defects cause inherited deafness
Date:2/17/2012

New Haven, Conn. Yale scientists have discovered the molecular pathway by which maternally inherited deafness appears to occur: Mitochondrial DNA mutations trigger a signaling cascade, resulting in programmed cell death. The study is in the Feb. 17 issue of Cell.

Mitochondria are cellular structures that function as "cellular power plants" because they generate most of the cell's supply of energy. They contain DNA inherited from one's mother. Mitochondria determine whether a cell lives or dies via the process of programmed cell death, or apoptosis.

The Yale scientists focused on a specific mitochondrial DNA mutation that causes maternally inherited deafness. The mutation occurs in a gene that codes for RNA in mitochondrial ribosomes, which generate proteins required for cellular respiration. The team found that cell lines containing this mutation are prone to cell death not directly due to the mutation, but rather because it enhanced a normal chemical modification of the RNA called methylation, which regulates ribosome assembly.

"Our lab had previously discovered that overexpression of the enzyme responsible for this methylation could cause cell death, even in cells without the deafness mutation," said corresponding author Gerald S. Shadel, professor of pathology and genetics at Yale School of Medicine. "But when the researchers overexpressed the enzyme in mice to mimic the effects of the mutation," he said, "we were astonished to discover that the animals progressively lost their hearing, reflecting how such disease would develop due to a known pathogenic human mitochondrial DNA mutation. This new mouse model will be instrumental in understanding genetic and environmental factors known to impact mitochondrial disease pathology."

The researchers found that reactive oxygen molecules produced by diseased mitochondria are what trigger events leading to a cell death-inducing gene expression program. By genetically depleting the protein ultimately responsible for activating this programmed cell death response, they were able to restore normal hearing to the mice.

The study not only sheds light on inherited deafness in humans, but possibly also age-related hearing loss and other human diseases. First author Nuno Raimundo, a postdoctoral associate in pathology, said, "Mitochondrial diseases are complicated because different tissues are affected in often unpredictable ways. Defining the molecular mechanism underlying death of only a specific subset of cells in the inner ear is a major step toward unraveling this complexity."


'/>"/>
Contact: Helen Dodson
helen.dodson@yale.edu
203-436-3984
Yale University
Source:Eurekalert

Related medicine news :

1. New mitochondrial control mechanism discovered
2. Animal results may pave way to treating rare mitochondrial diseases in children
3. Exposure to BPA may cause permanent fertility defects, Yale researchers find
4. Low blood oxygen may lead to heart defects in children with sickle cell disease
5. Many Non-U.S. Firms Affected by U.S. FDA Import Alert 80-04 for Medical Glove Manufacturing Defects, According to FDAImports.com, LLC
6. Psychotropic medications can cause birth defects
7. Experts Believe Many Birth Defects Are Preventable
8. Study implicates new epigenetic player in mental retardation and facial birth defects
9. Pediatric urologist performs innovative procedure for girls with rare vaginal defects
10. Growth defects in cystic fibrosis may start before birth
11. Doubled risk of anxiety for 18 month-old children with congenital heart defects
Post Your Comments:
*Name:
*Comment:
*Email:
(Date:10/13/2017)... (PRWEB) , ... October 13, 2017 , ... Apple ... care services, staged a mock evacuation of the facility as part of a disaster ... Fire Department, Echo Hose EMS and Shelton City Emergency Manager, as well as the ...
(Date:10/13/2017)... ... October 13, 2017 , ... Ellevate Network, the leading network for professional women, ... towards gender equality at their inaugural Summit in New York City in June. The ... social audience of over 3 million. To watch the Mobilize Women video, click ...
(Date:10/13/2017)... (PRWEB) , ... October 13, 2017 , ... ... will be giving viewers the lowdown on sciatica in a new episode of ... that focuses on current events and innovation and investigates each subject in-depth with ...
(Date:10/13/2017)... ... October 13, 2017 , ... “America On The Brink”: the ... “America On The Brink” is the creation of published author, William Nowers. Captain ... As a WWII veteran, he spent thirty years in the Navy. Following his ...
(Date:10/12/2017)... ... , ... Planet Fitness, one of the largest and fastest growing franchisors and ... flagship location in Covington, LA at 401 N. U.S. Highway 190, in January of ... Depot in the Holiday Square shopping center. Its location allows it to serve both ...
Breaking Medicine News(10 mins):
(Date:9/12/2017)... Sept. 12, 2017   EcoVadis , the leading platform for environmental, ... first annual edition of its Global CSR Risk and Performance Index. The ... EcoVadis, based on Scorecard Ratings that analyzed nearly 800,000 data points across ... ... ...
(Date:9/12/2017)... FRANCISCO , Sept. 12, 2017  ValGenesis ... Management Solutions (VLMS), is pleased to announce the ... a member of its Board of Directors and ... ValGenesis VLMS enables life science companies to manage ... the use of paper in this process. Furthermore, ...
(Date:9/9/2017)... Sept. 8, 2017 Dealmed Medical Supplies, ... of medical equipment, supplies, drugs, vaccines, and specialty medical ... into an agreement to acquire Vantage Medical Supplies, a ... Holtsville, New York . ... new and emerging medical practices, will operate under the ...
Breaking Medicine Technology: