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:6/27/2016)... ... June 27, 2016 , ... TopConsumerReviews.com recently awarded their ... Eyeglasses . , Millions of individuals in the United States and Canada wear eyeglasses. ... way to both correct vision and make a fashion statement. Even celebrities use glasses ...
(Date:6/26/2016)... Charlotte, NC (PRWEB) , ... June 26, 2016 , ... Brent Kasmer, a legally blind ... able to be personalized through a fitness app. The fitness app plans to fix the ... solutions currently only offer a one size fits all type program , They ...
(Date:6/25/2016)... ... , ... "With 30 hand-drawn hand gesture animations, FCPX users can easily customize ... Pixel Film Studios. , ProHand Cartoon’s package transforms over 1,300 hand-drawn pictures into ... Simply select a ProHand generator and drag it above media or text in the ...
(Date:6/25/2016)... , ... June 25, 2016 , ... Conventional wisdom preaches ... success. In terms of the latter, setting the bar too high can result in ... than just slow progress toward their goal. , Research from PsychTests.com ...
(Date:6/24/2016)... ... June 24, 2016 , ... The Pulmonary Hypertension ... that it will receive two significant new grants to support its work to ... its 25th anniversary by recognizing patients, medical professionals and scientists for their work ...
Breaking Medicine News(10 mins):
(Date:6/24/2016)... June 24, 2016 Research and Markets ... for Companion Diagnostic Tests" report to their offering. ... Companion Diagnostics The World Market for Companion ... medicine diagnostics. Market analysis in the report includes the following: ... (In Vitro Diagnostic Kits) by Region (N. America, EU, ROW), ...
(Date:6/24/2016)... Belgium , June 24, 2016 /PRNewswire/ ... announced the appointment of Dr. Edward Futcher ... a Non-Executive Director, effective June 23, 2016.Dr. Futcher ... and Nominations and Governance Committees.  As a non-executive ... provide independent expertise and strategic counsel to VolitionRx ...
(Date:6/23/2016)... June 23, 2016 Research and Markets ... Market - Forecast to 2022" report to their offering. ... method for the patients with kidney failure, it replaces the ... from the patient,s blood and thus the treatment helps to ... chloride in balance. Increasing number of ESRD ...
Breaking Medicine Technology: