Featured Research

from universities, journals, and other organizations

"Silent" DNA Speaks Up For The First Time -- Until Now, Half Of All Genes In Certain Cells Were Thought To Be Inexpressible

Date:
May 22, 2001
Source:
National Science Foundation
Summary:
By moderately raising the temperature of cells, biologists have broken through what was considered an impermeable barrier that kept half the genes in some cells "silent." The surprising results, in which these heated genes reached 500 times their normal rate of expression, could lead to better understanding of cellular processes involved in aging, fever and toxicity.

By moderately raising the temperature of cells, biologists have broken through what was considered an impermeable barrier that kept half the genes in some cells "silent." The surprising results, in which these heated genes reached 500 times their normal rate of expression, could lead to better understanding of cellular processes involved in aging, fever and toxicity.

Related Articles


Biochemistry and molecular biology professor David Gross and graduate student Edward Sekinger conducted the research at Louisiana State University Health Science Center (LSUHSC) with support from the National Science Foundation’s (NSF) Division of Molecular and Cellular Biosciences. The findings appear in the current issue of the journal Cell.

More than half the genes in a typical human cell never get expressed due to a shield-like coating of proteins called "chromatin." In many genes, chromatin does not prevent the expression of DNA’s genetic codes. But in genes coated with extremely dense "heterochromatin," the DNA stays quarantined from triggers that would otherwise cause transcription, the process by which genes dictate characteristics such as hair and eye color.

"Until now, genes sheathed in heterochromatin were assumed incapable of being expressed due to an absence of trigger proteins," Gross said. "This research shows that these proteins do naturally penetrate the heterochromatin, but once inside cannot function. Our evidence indicates that heating the cells activates these proteins, causing a heat-responsive gene to be expressed at a very high rate."

Using yeast as a model because it has many genes in common with humans, Gross and Sekinger raised the cells' temperature from its normal 86 degrees to 102 degrees. The cells woke up with a vengeance, expressing the silent, heat-responsive gene at 500 times the normal frequency.

Messenger RNA (mRNA) is a copy of the gene’s DNA that departs from a cell nucleus to transport genetic information. The researchers discovered that the enzyme responsible for producing mRNA is present even on the silent genes.

The process that makes some genes silent could itself help scientists understand aging. Yeast cells that contain elevated concentrations of the heterochromatin protein Sir2 show dramatically increased life-spans. Whereas the typical yeast cell multiplies about 25 times before dying -- compared to approximately 50 times in human cells -- yeast with twice the normal amount of Sir2 produce 30-percent more offspring.

"These findings could turn the gene-expression field upside down," Gross said. Apart from the possible implications for aging, the research could eventually help explain why certain cells are more vulnerable to fever and toxic chemicals, and how to control their negative effects.


Story Source:

The above story is based on materials provided by National Science Foundation. Note: Materials may be edited for content and length.


Cite This Page:

National Science Foundation. ""Silent" DNA Speaks Up For The First Time -- Until Now, Half Of All Genes In Certain Cells Were Thought To Be Inexpressible." ScienceDaily. ScienceDaily, 22 May 2001. <www.sciencedaily.com/releases/2001/05/010518082249.htm>.
National Science Foundation. (2001, May 22). "Silent" DNA Speaks Up For The First Time -- Until Now, Half Of All Genes In Certain Cells Were Thought To Be Inexpressible. ScienceDaily. Retrieved October 25, 2014 from www.sciencedaily.com/releases/2001/05/010518082249.htm
National Science Foundation. ""Silent" DNA Speaks Up For The First Time -- Until Now, Half Of All Genes In Certain Cells Were Thought To Be Inexpressible." ScienceDaily. www.sciencedaily.com/releases/2001/05/010518082249.htm (accessed October 25, 2014).

Share This



More Health & Medicine News

Saturday, October 25, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

IKEA Desk Converts From Standing to Sitting With One Button

IKEA Desk Converts From Standing to Sitting With One Button

Buzz60 (Oct. 24, 2014) IKEA is out with a new convertible desk that can convert from a sitting desk to a standing one with just the push of a button. Jen Markham explains. Video provided by Buzz60
Powered by NewsLook.com
Ebola Protective Suits Being Made in China

Ebola Protective Suits Being Made in China

AFP (Oct. 24, 2014) A factory in China is busy making Ebola protective suits for healthcare workers and others fighting the spread of the virus. Duration: 00:38 Video provided by AFP
Powered by NewsLook.com
WHO: Millions of Ebola Vaccine Doses by 2015

WHO: Millions of Ebola Vaccine Doses by 2015

AP (Oct. 24, 2014) The World Health Organization said on Friday that millions of doses of two experimental Ebola vaccines could be ready for use in 2015 and five more experimental vaccines would start being tested in March. (Oct. 24) Video provided by AP
Powered by NewsLook.com
Doctor in NYC Quarantined With Ebola

Doctor in NYC Quarantined With Ebola

AP (Oct. 24, 2014) An emergency room doctor who recently returned to the city after treating Ebola patients in West Africa has tested positive for the virus. He's quarantined in a hospital. (Oct. 24) Video provided by AP
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