Featured Research

from universities, journals, and other organizations

Nuclei in wrong place may be cause, not result, of inherited muscle diseases

Date:
December 16, 2013
Source:
American Society for Cell Biology
Summary:
Researchers solve the puzzle of whether out-of-position cell nuclei are cause or consequence of congenital muscle diseases.

Incorrectly positioned nuclei are not merely a sign but a possible cause of human congenital myopathies, a string of inherited muscle diseases, Victoria Schulman, graduate student at Weill Cornell Graduate School of Medical Sciences, and Mary Baylies, Ph.D., developmental biologist at the Sloan Kettering Institute of Memorial Sloan-Kettering Cancer Center (MSKCC) in New York City, reported at the American Society for Cell Biology annual meeting in New Orleans

Related Articles


The researchers found that the whimsically named fruitfly gene, Sunday Driver, a.k.a. syd, and its mammalian analog, JIP3, seem to be in the driver's seat when it comes to parking the multiple nuclei of a skeletal muscle cell in their correct places.

When the researchers mutated the syd gene in a fruitfly, Drosophila melanogaster, model system, the nuclei of both the embryonic and larval muscle tissue cells were unevenly spaced and clustered. The hatched larvae with defective Syd protein were hobbled, crawling much more slowly than their healthy counterparts. Adding mammalian JIP3 protein to the syd gene mutant flies resulted in normal nuclear spacing and locomotive ability.

Looking at flies to investigate the cell biology of human muscle diseases may seem like the long way around, but Schulman and Dr. Baylies said that they could get clearer answers to basic questions in the flexible fly model than in traditional human muscle cell cultures.

Congenital myopathies account for one-tenth of all neuromuscular disorders, causing deterioration of skeletal muscle and eventually death. Despite advances in research and medicine, there are currently no cures, and treatment is largely palliative.

Studying congenital myopathies such as EDMD poses special challenges for cell biologists. Unlike typical cells, which have a single nucleus located in the center of each cell, muscles are composed of long multi-nucleated cells with the nuclei strung out like seeds in a bean pod because muscle cells arise from the fusion of numerous myoblasts, the building blocks of muscles.

Post-fusion, the many nuclei within the new cell spread out to maximize inter-nuclear distance and usually move to the cell periphery to avoid interfering with muscle contraction. Skeletal muscle cells with unevenly spaced nuclei, or nuclei parked in the wrong spot, are telltale in tissue biopsies of patients with suspected inherited muscle disease such as EDMD (1/100,000 births) and centronuclear myopathy (1/50,000 births). And yet no one was certain whether out-of-position nuclei are a cause or consequence of muscle disease.

Using the fruit fly model system, Schulman and Dr. Baylies identified three types of proteins required for correct myonuclear positioning: cytoskeletal filaments known as microtubules, which serve as "tracks" or cellular "roadways"; the motor proteins kinesin and dynein, which travel along these tracks; and motor protein regulators such as Ensconsin and Sunday Driver (Syd). Mechanistically, Syd works as a control switch to activate one motor at a time to coordinate their collective efforts to pull and move muscle cell nuclei into correct positions.

"Collectively, we implicate syd as a necessary regulator of nuclear positioning in muscle tissue, and show that mispositioned nuclei are a possible cause, not a consequence, of muscle disease," the researchers wrote. They also point to the utility of model organisms in understanding a human disease as complex and dangerous as congenital myopathy.


Story Source:

The above story is based on materials provided by American Society for Cell Biology. Note: Materials may be edited for content and length.


Cite This Page:

American Society for Cell Biology. "Nuclei in wrong place may be cause, not result, of inherited muscle diseases." ScienceDaily. ScienceDaily, 16 December 2013. <www.sciencedaily.com/releases/2013/12/131216142529.htm>.
American Society for Cell Biology. (2013, December 16). Nuclei in wrong place may be cause, not result, of inherited muscle diseases. ScienceDaily. Retrieved April 1, 2015 from www.sciencedaily.com/releases/2013/12/131216142529.htm
American Society for Cell Biology. "Nuclei in wrong place may be cause, not result, of inherited muscle diseases." ScienceDaily. www.sciencedaily.com/releases/2013/12/131216142529.htm (accessed April 1, 2015).

Share This


More From ScienceDaily



More Health & Medicine News

Wednesday, April 1, 2015

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

7-Year-Old Girl Gets 3-D Printed 'robohand'

7-Year-Old Girl Gets 3-D Printed 'robohand'

AP (Mar. 31, 2015) — Although she never had much interest in prosthetic limbs before, Faith Lennox couldn&apos;t wait to slip on her new robohand. The 7-year-old, who lost part of her left arm when she was a baby, grabbed it as soon as it came off a 3-D printer. (March 31) Video provided by AP
Powered by NewsLook.com
Solitair Device Aims to Takes Guesswork out of Sun Safety

Solitair Device Aims to Takes Guesswork out of Sun Safety

Reuters - Innovations Video Online (Mar. 31, 2015) — The Solitair device aims to take the confusion out of how much sunlight we should expose our skin to. Small enough to be worn as a tie or hair clip, it monitors the user&apos;s sun exposure by taking into account their skin pigment, location and schedule. Matthew Stock reports. Video provided by Reuters
Powered by NewsLook.com
Soda, Salt and Sugar: The Next Generation of Taxes

Soda, Salt and Sugar: The Next Generation of Taxes

Washington Post (Mar. 30, 2015) — Denisa Livingston, a health advocate for the Dinι Community Advocacy Alliance, and the Post&apos;s Abby Phillip discuss efforts around the country to make unhealthy food choices hurt your wallet as much as your waistline. Video provided by Washington Post
Powered by NewsLook.com
UnitedHealth Buys Catamaran

UnitedHealth Buys Catamaran

Reuters - Business Video Online (Mar. 30, 2015) — The $12.8 billion merger will combine the U.S.&apos; third and fourth largest pharmacy benefit managers. Analysts say smaller PBMs could also merge. Fred Katayama reports. Video provided by Reuters
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
 
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:  

Breaking News:

Strange & Offbeat Stories

 

Health & Medicine

Mind & Brain

Living & Well

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:  

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile iPhone Android Web
Follow Facebook Twitter Google+
Subscribe RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins