Navigation Links
Scientists identify molecular cause for one form of deafness

Scientists exploring the physics of hearing have found an underlying molecular cause for one form of deafness, and a conceptual connection between deafness and the organization of liquid crystals, which are used in flat-panel displays.

Within the cochlea of the inner ear, sound waves cause the basilar membrane to vibrate. These vibrations stimulate hair cells, which then trigger nerve impulses that are transmitted to the brain.

Researchers have now learned that mutations in a protein called espin can cause floppiness in tiny bundles of protein filaments within the hair cells, impairing the passage of vibrations and resulting in deafness.

Filamentous actin (F-actin) is a rod-like protein that provides structural framework in living cells. F-actin is organized into bundles by espin, a linker protein found in sensory cells, including cochlear hair cells. Genetic mutations in espin's F-actin binding sites are linked to deafness in mice and humans.

"We found the structure of the bundles changes dramatically when normal espin is replaced with espin mutants that cause deafness," said Gerard Wong, a professor of materials science and engineering, of physics, and of bioengineering at the University of Illinois at Urbana-Champaign.

"The interior structure of the bundles changes from a rigid, hexagonal array of uniformly twisted filaments, to a liquid crystalline arrangement of filaments," Wong said. "Because the new organization causes the bundles to be more than a thousand times floppier, they cannot respond to sound in the same way. The rigidity of these bundles is essential for hearing."

Wong and his co-authors ?Illinois postdoctoral research associate Kirstin Purdy and Northwestern University professor of cell and molecular biology James R. Bartles ?report their findings in a paper accepted for publication in the journal Physical Review Letters, and posted on its Web site.

High-resolution X-ray diffraction exper iments, performed by Purdy at the Advanced Photon Source and at the Stanford Synchrotron Radiation Laboratory, allowed the researchers to solve the structure of various espin-actin bundles.

"As the ability of espin to cross-link F-actin is decreased by using genetically modified 'deafness' mutants with progressively more damaged actin binding sites, the structure changes from a well-ordered crystalline array of filaments to a nematic, liquid crystal-like state," said Wong, who also is a researcher at the Frederick Seitz Materials Research Laboratory on campus and at the university's Beckman Institute for Advanced Science and Technology.

In the liquid crystalline state, the bundles maintain their orientation order ?that is, they point roughly along the same direction ?but lose their positional order. These nematic liquid crystals are commonly used in watch displays and laptop displays.

Wong and his colleagues also found that a mixture of mutant espin and normal espin would prevent the structural transition from occurring. If gene expression could turn on the production of just a fraction of normal espin linkers, a kind of rescue attempt at restoring hearing could, in principle, be made.

"We have identified the underlying molecular cause for one form of deafness, and we have identified a mechanism to potentially 'rescue' this particular kind of pathology," Wong said. "Even so, this is really the first step. This work has relevance to not just human hearing, but also to artificial sensors."


'"/>

Source:University of Illinois at Urbana-Champaign


Related biology news :

1. Scientists ID molecular switch in liver that triggers harmful effects of saturated and trans fats
2. Scientists Replicate Hepatitis C Virus in Laboratory
3. Scientists detect probable genetic cause of some Parkinsons disease cases
4. Scientists find missing enzyme for tuberculosis iron scavenging pathway
5. Scientists seek answers on what activates deadly anthrax spores
6. Yale Scientists Find MicroRNA Regulates Ras Cancer Gene
7. Scientists collaborate to assess health of global environment
8. Scientists decipher genome of fungus that can cause life-threatening infections
9. Scientists discover the cellular roots of graying hair
10. Scientists rid stem cell culture of key animal cells
11. Scientists develop new color-coded test for protein folding
Post Your Comments:
*Name:
*Comment:
*Email:


(Date:3/31/2016)...   LegacyXChange, Inc. ... LegacyXChange is excited to release its first ... be launched online site for trading 100% guaranteed authentic ... also provide potential shareholders a sense of the value ... industry that is notorious for fraud. The video is ...
(Date:3/29/2016)... Florida , March 29, 2016 ... the "Company") LegacyXChange "LEGX" and SelectaDNA/CSI Protect are pleased ... in ink used in a variety of writing instruments, ... Buyers of originally created collectibles from athletes on LegacyXChange ... forensic analysis of the DNA. Bill ...
(Date:3/22/2016)... India , March 22, 2016 /PRNewswire/ ... market research report "Electronic Sensors Market for Consumer ... Proximity, & Others), Application (Communication & IT, ... Geography - Global Forecast to 2022", published ... industry is expected to reach USD 26.76 ...
Breaking Biology News(10 mins):
(Date:6/23/2016)... June 23, 2016 A person commits a crime, ... scene to track the criminal down. An outbreak ... and Drug Administration (FDA) uses DNA evidence to track down ... Sound far-fetched? It,s not. The FDA has increasingly used ... investigations of foodborne illnesses. Put as simply as possible, whole ...
(Date:6/23/2016)... , June 23, 2016   EpiBiome , ... secured $1 million in debt financing from Silicon Valley ... up automation and to advance its drug development efforts, ... new facility. "SVB has been an incredible ... the services a traditional bank would provide," said Dr. ...
(Date:6/23/2016)... , June 23, 2016  Blueprint Bio, a ... discoveries to the medical community, has closed its Series ... Matthew Nunez . "We have received a ... the capital we need to meet our current goals," ... provide us the runway to complete validation on the ...
(Date:6/23/2016)... Windsor, Connecticut (PRWEB) , ... June 23, 2016 ... ... will introduce a new line of intelligent tools designed, tuned and optimized exclusively ... place September 12–17 in Chicago. The result of a collaboration among several companies ...
Breaking Biology Technology: