Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Cellular transporter involved in gene silencing - Importin guides switch molecules to their targets

23.02.2009
Specific gene-silencing is involved in the development of cancer and plays an essential role in gene regulation. Small noncoding ribonucleic acids (miRNAs) are important regulators of genes.

In order to switch off a gene, they interact with so called Argonaute proteins - the subsequent complex induces the shutdown or even degradation of the genetic information. Until now, how this molecular switch works was widely unknown. Scientists of the Max Planck Institute of Biochemistry have now identified the protein Importin 8 as a central factor, that facilitates the switch molecule to find its target (Cell (2009), Cell 6th February, 2009).

Ribonucleic acids (RNAs) carry as messenger-RNAs (mRNAs) genetic information from DNA to cellular protein factories, where they are translated into proteins. But they also have important regulatory functions: Small noncoding RNAs (miRNAs) influence mRNA stability and are able to switch off genes by stalling their translation into proteins. Defects of these regulation processes may lead to cancer and neurodegenerative diseases. Therefore miRNAs are important objects of research and - in the future - could become the basis for new therapeutic strategies.

However, miRNAs can't shut off genes on their own: They need to form complexes with other proteins. As far as humans are concerned, the argonaute protein Ago-2 is the key cellular binding partner of miRNAs: The Ago-miRNA complex binds to mRNA and impedes their translation into proteins - either by blocking the translation process or by initiating RNA decomposition. "While there are a lot of studies concerning miRNA processing, the target mRNA recognition and binding by the Ago-miRNA-complex is only poorly understood", says Gunter Meister, the head of the research group "RNA biology" at the Max Planck Institute. Now his group has identified the first protein factor which is required for gene-silencing by Ago-miRNA-complexes: Importin 8.

Importin 8 interacts with Ago and miRNA and is necessary for the binding of the Ago-miRNA-complex to a variety of mRNA targets: In the cytoplasm - i.e. the intracellular space outside the nucleus - it recruits the complex to its target, allowing for efficient and specific gene-silencing. "Without Importin 8 no mRNA deactivation is possible", points Lasse Weinmann out, who conducted the study as part of his PhD thesis.

Furthermore, the scientists discovered a second mode of action of Importin 8: Importins are molecules that are responsible for the transport of proteins into the nucleus. "As we realised that our new factor is an Importin, it was an obvious supposition that transport processes might play a role in gene-silencing", explains Meister. Indeed the scientists proved that Importin 8 is involved in the transport of Ago-miRNA-complexes into the nucleus. This is especially interesting, because over the past years there have been controversial discussions as to whether or not small noncoding RNAs occur in the nucleus. "Our findings indicate that the Ago-miRNA-complex in the nucleus must serve a purpose. Possibly it is involved in gene regulation, too. But it is also conceivable, that there are other, yet unknown, functions", says Meister, "our results are a beginning to solving these questions".

Original Publication:
Weinmann et al.: Importin Is a Gene Silencing Factor that Targets Argonaute Proteins to Distinct mRNAs; Cell. 2009 Feb 6;136(3):496-507.
Contact:
Dr. Gunter Meister
RNA Biology
meister@biochem.mpg.de
Dr. Monika Gödde/Eva-Maria Diehl
Public Relations
Max Planck Institute of Biochemistry
Am Klopferpsitz 18
82152 Martinsried, Germany
Phone: +49 (89) 8578 2824
diehl@biochem.mpg.de

Eva-Maria Diehl | Max-Planck-Gesellschaft
Further information:
http://www.biochem.mpg.de/meister
http://www.biochem.mpg.de/en/news/pressroom

More articles from Life Sciences:

nachricht The birth of a new protein
20.10.2017 | University of Arizona

nachricht Building New Moss Factories
20.10.2017 | Albert-Ludwigs-Universität Freiburg im Breisgau

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Neutron star merger directly observed for the first time

University of Maryland researchers contribute to historic detection of gravitational waves and light created by event

On August 17, 2017, at 12:41:04 UTC, scientists made the first direct observation of a merger between two neutron stars--the dense, collapsed cores that remain...

Im Focus: Breaking: the first light from two neutron stars merging

Seven new papers describe the first-ever detection of light from a gravitational wave source. The event, caused by two neutron stars colliding and merging together, was dubbed GW170817 because it sent ripples through space-time that reached Earth on 2017 August 17. Around the world, hundreds of excited astronomers mobilized quickly and were able to observe the event using numerous telescopes, providing a wealth of new data.

Previous detections of gravitational waves have all involved the merger of two black holes, a feat that won the 2017 Nobel Prize in Physics earlier this month....

Im Focus: Smart sensors for efficient processes

Material defects in end products can quickly result in failures in many areas of industry, and have a massive impact on the safe use of their products. This is why, in the field of quality assurance, intelligent, nondestructive sensor systems play a key role. They allow testing components and parts in a rapid and cost-efficient manner without destroying the actual product or changing its surface. Experts from the Fraunhofer IZFP in Saarbrücken will be presenting two exhibits at the Blechexpo in Stuttgart from 7–10 November 2017 that allow fast, reliable, and automated characterization of materials and detection of defects (Hall 5, Booth 5306).

When quality testing uses time-consuming destructive test methods, it can result in enormous costs due to damaging or destroying the products. And given that...

Im Focus: Cold molecules on collision course

Using a new cooling technique MPQ scientists succeed at observing collisions in a dense beam of cold and slow dipolar molecules.

How do chemical reactions proceed at extremely low temperatures? The answer requires the investigation of molecular samples that are cold, dense, and slow at...

Im Focus: Shrinking the proton again!

Scientists from the Max Planck Institute of Quantum Optics, using high precision laser spectroscopy of atomic hydrogen, confirm the surprisingly small value of the proton radius determined from muonic hydrogen.

It was one of the breakthroughs of the year 2010: Laser spectroscopy of muonic hydrogen resulted in a value for the proton charge radius that was significantly...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ASEAN Member States discuss the future role of renewable energy

17.10.2017 | Event News

World Health Summit 2017: International experts set the course for the future of Global Health

10.10.2017 | Event News

Climate Engineering Conference 2017 Opens in Berlin

10.10.2017 | Event News

 
Latest News

Terahertz spectroscopy goes nano

20.10.2017 | Information Technology

Strange but true: Turning a material upside down can sometimes make it softer

20.10.2017 | Materials Sciences

NRL clarifies valley polarization for electronic and optoelectronic technologies

20.10.2017 | Interdisciplinary Research

VideoLinks
B2B-VideoLinks
More VideoLinks >>>