Featured Research

from universities, journals, and other organizations

Dual systems key to keeping chromosomes intact

Date:
March 7, 2013
Source:
University of Southern California
Summary:
Scientists have discovered how two different structural apparatuses collaborate to protect repetitive DNA when it is at its most vulnerable -- while it is being unzipped for replication.

Susan Forsburg, professor of molecular biology at the USC Dornsife College of Letters, Arts and Sciences.
Credit: Photo/Eric O'Connell

USC scientists have discovered how two different structural apparatuses collaborate to protect repetitive DNA when it is at its most vulnerable -- while it is being unzipped for replication.

Related Articles


The centromere -- the center of the "X" shape of a chromosome -- contains repeated DNA sequences that are epigenetically coded to attract so-called heterochromatin proteins. This protects the structure to ensure that the chromosomes separate properly.

If the heterochromatin is lost (due to mutations in the cell), the repetitive DNA becomes vulnerable to rearrangements and recombination. This is particularly true during DNA replication, when the DNA is transiently unwound to be copied.

If there are also defects in replication fork proteins that cause this process to be delayed or inefficient, the rearrangements are dramatically increased. This "genome instability" can lead to the loss of genetic information or genetic changes that can lead to cell death or cause cancer.

Susan Forsburg, who led the USC team that conducted the research, used yeast cells to show that simultaneously disrupting both heterochromatin and replication fork proteins caused significant increases in abnormal chromosomes, and in some cases, cell death.

"The insight here is really understanding the mechanism of how these different mutants create a lethal collaboration," said Forsburg, professor of molecular biology at the USC Dornsife College of Letters, Arts and Sciences. "Importantly, all the genes we study have human equivalents -- and mutations of some of these are already linked to cancer."

The research appears online in Cell Reports on March 7. Forsburg worked with Pao-Chen Li, formerly a graduate student at USC and now a postdoctoral researcher at the University of California, San Francisco, as well as Ruben Petreaca, Amanda Jensen, Ji-Ping Yuan and Marc Green, all from USC.

"We already knew epigenetic modifications change gene expression in cancer," Forsburg said. "Now we see a synergistic effect between the structural role of epigenetic modification that creates heterochromatin and replication fork stability."

The next step will be to identify additional components that show this same synergistic effect and to determine what other functions act with heterochromatin to preserve genome stability.

The research was funded by the National Science Foundation and the National Institutes of Health.


Story Source:

The above story is based on materials provided by University of Southern California. The original article was written by Robert Perkins. Note: Materials may be edited for content and length.


Journal Reference:

  1. Pao-Chen Li, Ruben C. Petreaca, Amanda Jensen, Ji-Ping Yuan, Marc D. Green, Susan L. Forsburg. Replication Fork Stability Is Essential for the Maintainenance of Centromere Integrity in the Absence of Heterochromatin. Cell Reports, 2013; DOI: 10.1016/j.celrep.2013.02.007

Cite This Page:

University of Southern California. "Dual systems key to keeping chromosomes intact." ScienceDaily. ScienceDaily, 7 March 2013. <www.sciencedaily.com/releases/2013/03/130307123951.htm>.
University of Southern California. (2013, March 7). Dual systems key to keeping chromosomes intact. ScienceDaily. Retrieved November 26, 2014 from www.sciencedaily.com/releases/2013/03/130307123951.htm
University of Southern California. "Dual systems key to keeping chromosomes intact." ScienceDaily. www.sciencedaily.com/releases/2013/03/130307123951.htm (accessed November 26, 2014).

Share This


More From ScienceDaily



More Health & Medicine News

Wednesday, November 26, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

From Popcorn To Vending Snacks: FDA Ups Calorie Count Rules

From Popcorn To Vending Snacks: FDA Ups Calorie Count Rules

Newsy (Nov. 25, 2014) — The US FDA is announcing new calorie rules on Tuesday that will require everywhere from theaters to vending machines to include calorie counts. Video provided by Newsy
Powered by NewsLook.com
Daily Serving Of Yogurt Could Reduce Risk Of Type 2 Diabetes

Daily Serving Of Yogurt Could Reduce Risk Of Type 2 Diabetes

Newsy (Nov. 25, 2014) — Need another reason to eat yogurt every day? Researchers now say it could reduce a person's risk of developing type 2 diabetes. Video provided by Newsy
Powered by NewsLook.com
Madagascar Working to Contain Plague Outbreak

Madagascar Working to Contain Plague Outbreak

AFP (Nov. 24, 2014) — Madagascar said Monday it is trying to contain an outbreak of plague -- similar to the Black Death that swept Medieval Europe -- that has killed 40 people and is spreading to the capital Antananarivo. Duration: 00:42 Video provided by AFP
Powered by NewsLook.com
Are Female Bosses More Likely To Be Depressed?

Are Female Bosses More Likely To Be Depressed?

Newsy (Nov. 24, 2014) — A new study links greater authority with increased depressive symptoms among women in the workplace. Video provided by Newsy
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