Featured Research

from universities, journals, and other organizations

Multiplication of cells under close observation

Date:
March 31, 2014
Source:
Université de Genève
Summary:
Cells must grow and divide optimally to ensure that our bodies functions properly. It is essential, however, that these processes are carefully controlled in order to prevent unrestrained proliferation that can lead to the formation of tumors. Researchers have uncovered a cellular factor that regulates the timing of DNA replication. This molecule, called Rif1, ensures that only a fraction of the origins of DNA replication is activated at specified times of the cell cycle.

The binding of Rif1 (red) to the PP1 enzyme (orange) inactivates DNA replication.
Credit: Image courtesy of Université de Genève

Our cells must grow and divide optimally to ensure that our bodies functions properly. It is essential, however, that these processes are carefully controlled in order to prevent unrestrained proliferation that can lead to the formation of tumours. David Shore, a professor at the Faculty of Sciences, University of Geneva (UNIGE), Switzerland, and his team have uncovered a cellular factor that regulates the timing of DNA replication. This molecule, called Rif1, ensures that only a fraction of the origins of DNA replication is activated at specified times of the cell cycle. The researchers' work, published in the journal Cell Reports, suggests that Rif1 plays a role in the prevention of "DNA replication stress," a process causing DNA damage that can lead to genome instability.

Related Articles


Each time a cell divides, it must replicate its DNA to provide a copy to the two daughter cells. This process starts at specific regions in the genome, known as "origins of replication." A number of proteins congregate at these sites in an orderly and sequential fashion. However, molecular 'tags' must be added to this protein complex by specific enzymes before replication can initiate.

Maintaining a temporal program for replication initiation

The molecular dialogue leading to the activation of replication origins must be strictly controlled in order to prevent replication from occurring too rapidly, thus overloading the system. "Under normal conditions, there are many more replication origins than are actually used. We suspect that in precancerous cells many of these normally dormant origins are activated inappropriately," notes David Shore, professor in the Department of Molecular Biology of the UNIGE. Are there safeguards which intervene directly at the level of the origins of replication? This is what the researchers at UNIGE tried to find out by using yeast, a unicellular fungus that is used as a model organism because it functions in many respects like a mammalian cell. "We wanted to determine the possible role of a protein named Rif1 since it was recently implicated in controlling DNA replication in several organisms, including yeast and human cells," reports Stefano Mattarocci, lead author of the study.

Simply remove the molecular tags

In collaboration with researchers from the Friedrich Miescher Institute of Basel and the Vanderbilt University Medical Center of Nashville (United States), the biologists discovered that Rif1 regulates the timing of DNA replication by acting directly at the level of the origins of replication. "Rif1 recruits a specific enzyme called PP1, which will remove the molecular 'tags' required to start the replication process," explains Maksym Shyian, co-lead author of the article.

The binding of Rif1 to this enzyme curbs the untimely triggering of DNA replication. "These safeguards are probably part of a system that prevents DNA replication stress," reports David Shore. This stress, which is notably induced in pre-cancerous lesions, is characterised by an increased DNA replication rate, which provokes DNA damage and genome instability, major drivers of tumor formation.


Story Source:

The above story is based on materials provided by Université de Genève. Note: Materials may be edited for content and length.


Journal Reference:

  1. Stefano Mattarocci, Maksym Shyian, Laure Lemmens, Pascal Damay, Dogus Murat Altintas, Tianlai Shi, Clinton R. Bartholomew, Nicolas H. Thomä, Christopher F.J. Hardy, David Shore. Rif1 Controls DNA Replication Timing in Yeast through the PP1 Phosphatase Glc7. Cell Reports, 2014; DOI: 10.1016/j.celrep.2014.03.010

Cite This Page:

Université de Genève. "Multiplication of cells under close observation." ScienceDaily. ScienceDaily, 31 March 2014. <www.sciencedaily.com/releases/2014/03/140331084008.htm>.
Université de Genève. (2014, March 31). Multiplication of cells under close observation. ScienceDaily. Retrieved November 24, 2014 from www.sciencedaily.com/releases/2014/03/140331084008.htm
Université de Genève. "Multiplication of cells under close observation." ScienceDaily. www.sciencedaily.com/releases/2014/03/140331084008.htm (accessed November 24, 2014).

Share This


More From ScienceDaily



More Plants & Animals News

Monday, November 24, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Winter Can Cause Depression — Here's How To Combat It

Winter Can Cause Depression — Here's How To Combat It

Newsy (Nov. 23, 2014) — Millions of American suffer from seasonal depression every year. It can lead to adverse health effects, but there are ways to ease symptoms. Video provided by Newsy
Powered by NewsLook.com
Ebola-Hit Sierra Leone's Late Cocoa Leaves Bitter Taste

Ebola-Hit Sierra Leone's Late Cocoa Leaves Bitter Taste

AFP (Nov. 23, 2014) — The arable district of Kenema in Sierra Leone -- at the centre of the Ebola outbreak in May -- has been under quarantine for three months as the cocoa harvest comes in. Duration: 01:32 Video provided by AFP
Powered by NewsLook.com
Anglerfish Rarely Seen In Its Habitat Will Haunt You

Anglerfish Rarely Seen In Its Habitat Will Haunt You

Newsy (Nov. 22, 2014) — For the first time Monterey Bay Aquarium recorded a video of the elusive, creepy and rarely seen anglerfish. Video provided by Newsy
Powered by NewsLook.com
Birds Around the World Take Flight

Birds Around the World Take Flight

Reuters - Light News Video Online (Nov. 22, 2014) — An imperial eagle equipped with a camera spreads its wings over London. It's just one of the many birds making headlines in this week's "animal roundup". Jillian Kitchener 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

 

Plants & Animals

Earth & Climate

Fossils & Ruins

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