Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Scientists develop new RNAi knockdown technology

02.06.2003


Scientists from the RIKEN Tsukuba Institute (Japan) have developed a valuable new experimental system for tissue-specific RNAi knockdown in mammalian cells and organisms – a discovery that will markedly advance the functional characterization of genes involved in development and disease.



Discovered in the late nineties, RNA intereference (RNAi) refers to the introduction of double-stranded RNA (dsRNA) into a cell, where it induces the degradation of complementary mRNA, and thereby suppresses gene expression. RNAi has proven to be a powerful tool in the elucidation of gene function in organisms ranging from worms, to plants and fruit flies.

However, the use of RNAi in mammals has been complicated by the antiviral response of mammalian cells to dsRNA. The presence of foreign dsRNA in a mammalian cell initiates the so-called "interferon response:" the non-specific degradation of mRNA, and ensuing death of the cell. Mammalian RNAi researchers have undertaken a few different routes to avoid eliciting the interferon response, and while some have been successful, none have been able to accomplish it in a tissue-specific manner. Until now.


As published in the June 1 issue of Genes & Development, Dr. Shunsuke Ishii and colleagues have constructed a new RNAi vector (a vehicle to introduce foreign RNA into a cell), which both side steps the interferon response and allows for the tissue-specific suppression of gene expression. This vector, called pDECAP, represents a dramatic improvement over current RNAi transgenic technology.

As Dr. Ishii explains, "In the RNAi transgenic systems developed so far, small hairpin-type RNA is expressed from the RNA polymerase III promoter or the virus promoter. However, these systems cannot be utilized to knockdown gene function in a tissue-specific manner, because these promoters are active in all types of cells. In our system, the RNA polymerase II promoter is utilized to express hairpin-type double-strand RNA (dsRNA). Therefore, our system can be used to generate the tissue-specific knockdown mice."

The pDECAP vector expresses dsRNA from an RNA polymerase II promoter, which can be actived in specific cell types. Therefore, Dr. Ishii and colleagues can pick and choose which tissues that they want to knockdown gene function in. To avoid the interferon response, Dr. Ishii and colleagues engineered the vector to transcribe dsRNA that lacks the sequences needed to export it from the nucleus into the cytosol. Instead, pDECAP-expressed dsRNA is sequestered in the nucleus, where it is processed into small interfering RNAs (siRNAs). These siRNAs are then released into the cytosol, where they direct the degradation of target mRNA without eliciting the interferon response.

Dr. Ishii and colleagues used the pDECAP system to suppress expression of the Ski oncogene in mice. These Ski-knockdown mice largely recapitulate the mutant phenotype of traditional Ski-knockout mice (in which the Ski gene has been deleted through homologous recombination of embryonic stem cells), suggesting that Dr. Ishii’s new system provides an efficient alternative to traditional mouse knockouts in the exploration of gene function.

Heather Cosel | EurekAlert!
Further information:
http://www.cshl.org/

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 >>>