Featured Research

from universities, journals, and other organizations

Enzyme corrects more than one million faults in DNA replication

Date:
May 10, 2012
Source:
University of Edinburgh
Summary:
Scientists have discovered that one enzyme corrects more than one million faults in DNA replication. And, it corrects the most common mistake in mammalian DNA.

Scientists from the Medical Research Council (MRC) Institute of Genetics and Molecular Medicine (IGMM) at the University of Edinburgh have discovered an enzyme that corrects the most common mistake in mammalian DNA.

The mistake is the inclusion of individual bits of RNA within the DNA sequence, which the researchers found occurs more than a million times in each cell as it divides. The findings, published in Cell, suggest the RNase H2 enzyme is central to an important DNA repair mechanism necessary to protect the human genome.

Each time a cell divides it must first make an identical copy of its entire genetic material, known as the genome. During this process, which is called DNA replication, the integrity of the genetic code is safeguarded by cellular 'proofreading' and error checking mechanisms.

But sometimes mistakes creep into the genetic code, which if not corrected could lead to genetic disease or cancer. Accidental incorporation of RNA is one such mistake. The individual building blocks of RNA (ribonucleotides) are very similar to those that make up DNA, however, they are much less stable and if they remain incorporated in DNA they cause harmful breaks in the double helix. Such breaks are common in cancer cells.

The researchers made the discovery while working on a rare childhood auto-immune disease known as Aicardi-Goutières syndrome, which is caused by mutations in the RNase H2 genes. It leads to inflammation of the brain soon after birth and can be fatal within the first few years of life.

To study this condition in more detail, the scientists knocked out one of the RNase H2 genes in mice. They found that without the enzyme, the developing mouse embryos accumulated more than 1,000,000 single embedded bits of RNA in the genome of every cell, resulting in instability of their DNA.

Dr Andrew Jackson from the MRC IGMM at the University of Edinburgh, who led the research, said:

"The most amazing thing is that by working to understand a rare genetic disease, we've uncovered the most common fault in DNA replication by far, which we didn't even start out looking for! More surprising still is that a single enzyme is so crucial to repairing over a million faults in the DNA of each cell, to protect the integrity of our entire genetic code.

"We expect our findings to have broad implications in the fields of autoimmunity and cancer in the future, but first we need to find out more about what effect the incorporation of RNA nucleotides is actually having on the genome."

Professor Nick Hastie, director of the MRC IGMM at the University of Edinburgh, said:

"This study is a fantastic example of clinicians working alongside laboratory scientists towards a shared goal of improving our understanding of human health and disease. Such progress would not be possible without the critical mass of scientists at the IGMM, with capabilities in many key areas coupled with access to patient data and clinical expertise."


Story Source:

The above story is based on materials provided by University of Edinburgh. Note: Materials may be edited for content and length.


Journal Reference:

  1. Martin A.M. Reijns, Björn Rabe, Rachel E. Rigby, Pleasantine Mill, Katy R. Astell, Laura A. Lettice, Shelagh Boyle, Andrea Leitch, Margaret Keighren, Fiona Kilanowski, Paul S. Devenney, David Sexton, Graeme Grimes, Ian J. Holt, Robert E. Hill, Martin S. Taylor, Kirstie A. Lawson, Julia R. Dorin, Andrew P. Jackson. Enzymatic Removal of Ribonucleotides from DNA Is Essential for Mammalian Genome Integrity and Development. Cell, 2012; DOI: 10.1016/j.cell.2012.04.011

Cite This Page:

University of Edinburgh. "Enzyme corrects more than one million faults in DNA replication." ScienceDaily. ScienceDaily, 10 May 2012. <www.sciencedaily.com/releases/2012/05/120510122809.htm>.
University of Edinburgh. (2012, May 10). Enzyme corrects more than one million faults in DNA replication. ScienceDaily. Retrieved September 24, 2014 from www.sciencedaily.com/releases/2012/05/120510122809.htm
University of Edinburgh. "Enzyme corrects more than one million faults in DNA replication." ScienceDaily. www.sciencedaily.com/releases/2012/05/120510122809.htm (accessed September 24, 2014).

Share This



More Health & Medicine News

Wednesday, September 24, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Ebola Costs Keep Mounting

Ebola Costs Keep Mounting

Reuters - Business Video Online (Sep. 23, 2014) — The WHO has warned up to 20,000 people could be infected with Ebola over the next few weeks. As Sonia Legg reports, the implications for the West African countries suffering from the disease are huge. Video provided by Reuters
Powered by NewsLook.com
Ebola Cases Could Reach 1.4 Million Within 4 Months

Ebola Cases Could Reach 1.4 Million Within 4 Months

Newsy (Sep. 23, 2014) — Health officials warn that without further intervention, the number of Ebola cases in Liberia and Sierra Leone could reach 1.4 million by January. Video provided by Newsy
Powered by NewsLook.com
WHO: Ebola Cases to Triple in Weeks Without Drastic Action

WHO: Ebola Cases to Triple in Weeks Without Drastic Action

AFP (Sep. 23, 2014) — The number of Ebola infections will triple to 20,000 by November, soaring by thousands every week if efforts to stop the outbreak are not stepped up radically, the WHO warned in a study on Tuesday. Duration: 01:01 Video provided by AFP
Powered by NewsLook.com
5 Ways Men Can Prevent Most Heart Attacks

5 Ways Men Can Prevent Most Heart Attacks

Newsy (Sep. 23, 2014) — No surprise here: A recent study says men can reduce their risk of heart attack by maintaining a healthy lifestyle, which includes daily exercise. 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