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 Water forms 'spine of hydration' around DNA, group finds
26.05.2017 | Cornell University

nachricht How herpesviruses win the footrace against the immune system
26.05.2017 | Helmholtz-Zentrum für Infektionsforschung

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Can the immune system be boosted against Staphylococcus aureus by delivery of messenger RNA?

Staphylococcus aureus is a feared pathogen (MRSA, multi-resistant S. aureus) due to frequent resistances against many antibiotics, especially in hospital infections. Researchers at the Paul-Ehrlich-Institut have identified immunological processes that prevent a successful immune response directed against the pathogenic agent. The delivery of bacterial proteins with RNA adjuvant or messenger RNA (mRNA) into immune cells allows the re-direction of the immune response towards an active defense against S. aureus. This could be of significant importance for the development of an effective vaccine. PLOS Pathogens has published these research results online on 25 May 2017.

Staphylococcus aureus (S. aureus) is a bacterium that colonizes by far more than half of the skin and the mucosa of adults, usually without causing infections....

Im Focus: A quantum walk of photons

Physicists from the University of Würzburg are capable of generating identical looking single light particles at the push of a button. Two new studies now demonstrate the potential this method holds.

The quantum computer has fuelled the imagination of scientists for decades: It is based on fundamentally different phenomena than a conventional computer....

Im Focus: Turmoil in sluggish electrons’ existence

An international team of physicists has monitored the scattering behaviour of electrons in a non-conducting material in real-time. Their insights could be beneficial for radiotherapy.

We can refer to electrons in non-conducting materials as ‘sluggish’. Typically, they remain fixed in a location, deep inside an atomic composite. It is hence...

Im Focus: Wafer-thin Magnetic Materials Developed for Future Quantum Technologies

Two-dimensional magnetic structures are regarded as a promising material for new types of data storage, since the magnetic properties of individual molecular building blocks can be investigated and modified. For the first time, researchers have now produced a wafer-thin ferrimagnet, in which molecules with different magnetic centers arrange themselves on a gold surface to form a checkerboard pattern. Scientists at the Swiss Nanoscience Institute at the University of Basel and the Paul Scherrer Institute published their findings in the journal Nature Communications.

Ferrimagnets are composed of two centers which are magnetized at different strengths and point in opposing directions. Two-dimensional, quasi-flat ferrimagnets...

Im Focus: World's thinnest hologram paves path to new 3-D world

Nano-hologram paves way for integration of 3-D holography into everyday electronics

An Australian-Chinese research team has created the world's thinnest hologram, paving the way towards the integration of 3D holography into everyday...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Marine Conservation: IASS Contributes to UN Ocean Conference in New York on 5-9 June

24.05.2017 | Event News

AWK Aachen Machine Tool Colloquium 2017: Internet of Production for Agile Enterprises

23.05.2017 | Event News

Dortmund MST Conference presents Individualized Healthcare Solutions with micro and nanotechnology

22.05.2017 | Event News

 
Latest News

How herpesviruses win the footrace against the immune system

26.05.2017 | Life Sciences

Water forms 'spine of hydration' around DNA, group finds

26.05.2017 | Life Sciences

First Juno science results supported by University of Leicester's Jupiter 'forecast'

26.05.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>