Featured Research

from universities, journals, and other organizations

UT Southwestern Researchers Find Another Clue To Secrets Of Cellular Aging

Date:
June 18, 2001
Source:
University Of Texas Southwestern Medical Center At Dallas
Summary:
A discovery by UT Southwestern Medical Center at Dallas scientists that genes near human telomeres can be silenced may help explain how and why humans age.

DALLAS - June 15, 2001 - A discovery by UT Southwestern Medical Center at Dallas scientists that genes near human telomeres can be silenced may help explain how and why humans age.

Related Articles


Telomeres are repeating sequences of DNA located at the end of each chromosome and are believed to function as a counting mechanism for cellular aging.

Dr. Jerry Shay and Dr. Woodring Wright, UT Southwestern professors of cell biology, report in today's issue of Science that human cells can exhibit telomere position effect (TPE), a mechanism by which genes near telomeres can be turned off, and that the strength of gene silencing is proportional to the length of nearby telomeres.

Shay and Wright, along with collaborators at UT Southwestern, have previously shown that human cells age each time they divide because their telomeres shorten. After a finite number of cell divisions - when telomeres become short - the cells stop dividing.

Most normal cells lack the enzyme telomerase, which maintains telomeres. Telomerase is activated in 90 percent of all cancers, in which cells continue to divide at a high rate. Many diseases, including Down syndrome, are characterized by premature aging. Further understanding of TPE could help researchers discover how cellular aging contributes to the overall aging process.

"This is an important step in trying to explain the connection between telomere shortening and aging," Shay said. "Normal cells will only grow for a limited time. They grow for a while, and then they go through a process called senescence, or aging. We wanted to know about the molecular memory. Are cells counting how many times they divide? We believe the telomeres are the molecular memory."

The researchers incorporated a piece of DNA containing a luciferase (the enzyme that allows fireflies to emit light) gene into human cells and showed that if it became located at the

telomere, there was 10 times less luciferase activity than if it was located in the middle of a chromosome. They also found an even greater decrease in luciferase activity if they used telomerase to make the telomeres grow longer.

"We knew that when telomeres became too short, they caused cells to stop dividing, but there wasn't a mechanism for how a cell could sense how long its telomeres were before they became too short. TPE can do that. It can let a cell know how old it is so that it could change its behavior before it became senescent," Wright said.

TPE could help explain the differences between young and old cells. For example, if there were "aging" genes next to telomeres, they would be silent when the cells were young. As the cells aged and continued to divide, their telomeres would shorten; the silencing of the genes would be reversed; and the "aging" genes activated.

The researchers are now looking for naturally occurring human genes located near telomeres whose expression is influenced by telomere length.

Joseph A. Baur, a UT Southwestern student research assistant in cell biology, and Dr. Ying Zou, a UT Southwestern cell biology fellow, also were involved in the research.

Shay and Wright's earlier research has shown that telomerase causes human cells grown in the laboratory to retain their "youth" and continue to divide long past the time when they normally would have stopped dividing. This discovery is making the use of normal cells for tissue engineering and other therapeutic uses much easier.

The investigators' Web site can be found at http://www.swmed.edu/home_pages/cellbio/shay-wright.


Story Source:

The above story is based on materials provided by University Of Texas Southwestern Medical Center At Dallas. Note: Materials may be edited for content and length.


Cite This Page:

University Of Texas Southwestern Medical Center At Dallas. "UT Southwestern Researchers Find Another Clue To Secrets Of Cellular Aging." ScienceDaily. ScienceDaily, 18 June 2001. <www.sciencedaily.com/releases/2001/06/010615071927.htm>.
University Of Texas Southwestern Medical Center At Dallas. (2001, June 18). UT Southwestern Researchers Find Another Clue To Secrets Of Cellular Aging. ScienceDaily. Retrieved October 31, 2014 from www.sciencedaily.com/releases/2001/06/010615071927.htm
University Of Texas Southwestern Medical Center At Dallas. "UT Southwestern Researchers Find Another Clue To Secrets Of Cellular Aging." ScienceDaily. www.sciencedaily.com/releases/2001/06/010615071927.htm (accessed October 31, 2014).

Share This



More Health & Medicine News

Friday, October 31, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Fauci Says Ebola Risk in US "essentially Zero"

Fauci Says Ebola Risk in US "essentially Zero"

AP (Oct. 30, 2014) NIAID Director Anthony Fauci said the risk of Ebola becoming an epidemic in the U.S. is essentially zero Thursday at the Washington Ideas Forum. He also said an Ebola vaccine will be tested in West Africa in the next few months. (Oct. 30) Video provided by AP
Powered by NewsLook.com
Nurse Defies Ebola Quarantine With Bike Ride

Nurse Defies Ebola Quarantine With Bike Ride

AP (Oct. 30, 2014) A nurse who vowed to defy Maine's voluntary quarantine for health care workers who treated Ebola patients followed through on her promise Thursday, leaving her home for an hour-long bike ride. (Oct. 30) Video provided by AP
Powered by NewsLook.com
Pot-Infused Edibles Raise Concerns in Colorado

Pot-Infused Edibles Raise Concerns in Colorado

AFP (Oct. 30, 2014) Colorado may have legalized marijuana for recreational use, but the debate around the decision still continues, with a recent - failed - attempt to ban cannabis-infused edibles. Duration: 01:53 Video provided by AFP
Powered by NewsLook.com
British Navy Ship Arrives in Sierra Leone With Ebola Aid

British Navy Ship Arrives in Sierra Leone With Ebola Aid

AFP (Oct. 30, 2014) The British ship RFA ARGUS arrived in Sierra Leone to deliver supplies and equipment to help the fight against Ebola. Duration: 00:42 Video provided by AFP
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