Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Stopgap DNA Repair Needs a Second Step

06.05.2009
DNA is damaged about 20,000 times a day. Sometimes this damage causes gaps that prevent the DNA molecule from being copied when the cell divides. In a sloppy but efficient repair technique, the cell may fill in the missing DNA in an inaccurate fashion. Such repair can save the cell from dying, but it comes at a price: this error-prone mechanism is a major source of mutations. Now, a scientist at the Weizmann Institute has revealed how the stopgap repair works. It proceeds in two steps and requires two types of enzymes.

One can have a dream, two can make that dream so real, goes a popular song. Now a Weizmann Institute study has revealed that it takes two to perform an essential form of DNA repair.

Prof. Zvi Livneh of the Weizmann Institute’s Biological Chemistry Department has been studying DNA repair for some two decades: “Considering that the DNA of each cell is damaged about 20,000 times a day by radiation, pollutants, and harmful chemicals produced within the body, it’s obvious that without effective DNA repair, life as we know it could not exist.

Most types of damage result in individual mutations – genetic ‘spelling mistakes’ – that are corrected by precise, error-free repair enzymes. Sometimes, however, damage results in more than a mere spelling mistake; it can cause gaps in the DNA, which prevent the DNA molecule from being copied when the cell divides, much like an ink blot or a hole on a book page interferes with reading. So dangerous are these gaps that the cell resorts to a sloppy but efficient repair technique to avoid them: it fills in the missing DNA in an inaccurate fashion. Such repair can save the cell from dying, but it comes at a price: this error-prone mechanism, discovered at the Weizmann Institute and elsewhere about a decade ago, is a major source of mutations.”

In a recent study he conducted with graduate students Sigal Shachar and Omer Ziv, as well as researchers from the US and Germany, Livneh revealed how the error-prone repair works. The team found that such repair proceeds in two steps and requires two types of enzymes, belonging to the family of enzymes called DNA polymerases, which synthesize DNA. First, one repair enzyme, “the inserter,” does its best to fit a genetic “letter” into the gap, opposite the damaged site in the DNA molecule; several enzymes can perform this initial step, which often results in the insertion of an incorrect genetic letter. Next, another enzyme, “the extender,” helps to restore regular copying of DNA by attaching additional DNA letters after the damaged site; only one repair enzyme is capable of performing this vital second step. These findings were published recently in The EMBO Journal.

Understanding how this major form of DNA repair works can have significant clinical implications. Since defects in this process increase the risk of cancer, clarifying its nuts and bolts might one day make it possible to enhance it in people whose natural DNA repair is deficient. In addition, manipulating this mechanism can improve the effectiveness of cancer drugs. Cancer cells can resist chemotherapy by exploiting their natural repair mechanisms, and blocking these mechanisms may help overcome this resistance, leading to a targeted destruction of the cancerous tumor.

Prof. Zvi Livneh’s research is supported by the Helen and Martin Kimmel Institute for Stem Cell Research; the estate of Lore F. Leder; and Esther Smidof, Geneva, Switzerland. Prof. Livneh is the incumbent of the Maxwell Ellis Professorial Chair in Biomedical Research.

The Weizmann Institute of Science in Rehovot, Israel, is one of the world's top-ranking multidisciplinary research institutions. Noted for its wide-ranging exploration of the natural and exact sciences, the Institute is home to 2,600 scientists, students, technicians, and supporting staff. Institute research efforts include the search for new ways of fighting disease and hunger, examining leading questions in mathematics and computer science, probing the physics of matter and the universe, creating novel materials, and developing new strategies for protecting the environment.

Jennifer Manning | Newswise Science News
Further information:
http://www.acwis.org
http://www.weizmann-usa.org/site/PageServer?pagename=homepage

More articles from Life Sciences:

nachricht Nanoparticle Exposure Can Awaken Dormant Viruses in the Lungs
16.01.2017 | Helmholtz Zentrum München - Deutsches Forschungszentrum für Gesundheit und Umwelt

nachricht Cholera bacteria infect more effectively with a simple twist of shape
13.01.2017 | Princeton University

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Interfacial Superconductivity: Magnetic and superconducting order revealed simultaneously

Researchers from the University of Hamburg in Germany, in collaboration with colleagues from the University of Aarhus in Denmark, have synthesized a new superconducting material by growing a few layers of an antiferromagnetic transition-metal chalcogenide on a bismuth-based topological insulator, both being non-superconducting materials.

While superconductivity and magnetism are generally believed to be mutually exclusive, surprisingly, in this new material, superconducting correlations...

Im Focus: Studying fundamental particles in materials

Laser-driving of semimetals allows creating novel quasiparticle states within condensed matter systems and switching between different states on ultrafast time scales

Studying properties of fundamental particles in condensed matter systems is a promising approach to quantum field theory. Quasiparticles offer the opportunity...

Im Focus: Designing Architecture with Solar Building Envelopes

Among the general public, solar thermal energy is currently associated with dark blue, rectangular collectors on building roofs. Technologies are needed for aesthetically high quality architecture which offer the architect more room for manoeuvre when it comes to low- and plus-energy buildings. With the “ArKol” project, researchers at Fraunhofer ISE together with partners are currently developing two façade collectors for solar thermal energy generation, which permit a high degree of design flexibility: a strip collector for opaque façade sections and a solar thermal blind for transparent sections. The current state of the two developments will be presented at the BAU 2017 trade fair.

As part of the “ArKol – development of architecturally highly integrated façade collectors with heat pipes” project, Fraunhofer ISE together with its partners...

Im Focus: How to inflate a hardened concrete shell with a weight of 80 t

At TU Wien, an alternative for resource intensive formwork for the construction of concrete domes was developed. It is now used in a test dome for the Austrian Federal Railways Infrastructure (ÖBB Infrastruktur).

Concrete shells are efficient structures, but not very resource efficient. The formwork for the construction of concrete domes alone requires a high amount of...

Im Focus: Bacterial Pac Man molecule snaps at sugar

Many pathogens use certain sugar compounds from their host to help conceal themselves against the immune system. Scientists at the University of Bonn have now, in cooperation with researchers at the University of York in the United Kingdom, analyzed the dynamics of a bacterial molecule that is involved in this process. They demonstrate that the protein grabs onto the sugar molecule with a Pac Man-like chewing motion and holds it until it can be used. Their results could help design therapeutics that could make the protein poorer at grabbing and holding and hence compromise the pathogen in the host. The study has now been published in “Biophysical Journal”.

The cells of the mouth, nose and intestinal mucosa produce large quantities of a chemical called sialic acid. Many bacteria possess a special transport system...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

12V, 48V, high-voltage – trends in E/E automotive architecture

10.01.2017 | Event News

2nd Conference on Non-Textual Information on 10 and 11 May 2017 in Hannover

09.01.2017 | Event News

Nothing will happen without batteries making it happen!

05.01.2017 | Event News

 
Latest News

Water - as the underlying driver of the Earth’s carbon cycle

17.01.2017 | Earth Sciences

Interfacial Superconductivity: Magnetic and superconducting order revealed simultaneously

17.01.2017 | Materials Sciences

Smart homes will “LISTEN” to your voice

17.01.2017 | Architecture and Construction

VideoLinks
B2B-VideoLinks
More VideoLinks >>>