Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


Scientists develop new RNAi knockdown technology


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:

More articles from Life Sciences:

nachricht First time-lapse footage of cell activity during limb regeneration
25.10.2016 | eLife

nachricht Phenotype at the push of a button
25.10.2016 | Institut für Pflanzenbiochemie

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Light-driven atomic rotations excite magnetic waves

Terahertz excitation of selected crystal vibrations leads to an effective magnetic field that drives coherent spin motion

Controlling functional properties by light is one of the grand goals in modern condensed matter physics and materials science. A new study now demonstrates how...

Im Focus: New 3-D wiring technique brings scalable quantum computers closer to reality

Researchers from the Institute for Quantum Computing (IQC) at the University of Waterloo led the development of a new extensible wiring technique capable of controlling superconducting quantum bits, representing a significant step towards to the realization of a scalable quantum computer.

"The quantum socket is a wiring method that uses three-dimensional wires based on spring-loaded pins to address individual qubits," said Jeremy Béjanin, a PhD...

Im Focus: Scientists develop a semiconductor nanocomposite material that moves in response to light

In a paper in Scientific Reports, a research team at Worcester Polytechnic Institute describes a novel light-activated phenomenon that could become the basis for applications as diverse as microscopic robotic grippers and more efficient solar cells.

A research team at Worcester Polytechnic Institute (WPI) has developed a revolutionary, light-activated semiconductor nanocomposite material that can be used...

Im Focus: Diamonds aren't forever: Sandia, Harvard team create first quantum computer bridge

By forcefully embedding two silicon atoms in a diamond matrix, Sandia researchers have demonstrated for the first time on a single chip all the components needed to create a quantum bridge to link quantum computers together.

"People have already built small quantum computers," says Sandia researcher Ryan Camacho. "Maybe the first useful one won't be a single giant quantum computer...

Im Focus: New Products - Highlights of COMPAMED 2016

COMPAMED has become the leading international marketplace for suppliers of medical manufacturing. The trade fair, which takes place every November and is co-located to MEDICA in Dusseldorf, has been steadily growing over the past years and shows that medical technology remains a rapidly growing market.

In 2016, the joint pavilion by the IVAM Microtechnology Network, the Product Market “High-tech for Medical Devices”, will be located in Hall 8a again and will...

All Focus news of the innovation-report >>>



Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

Agricultural Trade Developments and Potentials in Central Asia and the South Caucasus

14.10.2016 | Event News

World Health Summit – Day Three: A Call to Action

12.10.2016 | Event News

Latest News

Enormous dome in central Andes driven by huge magma body beneath it

25.10.2016 | Earth Sciences

First time-lapse footage of cell activity during limb regeneration

25.10.2016 | Life Sciences

Deep down fracking wells, microbial communities thrive

25.10.2016 | Earth Sciences

More VideoLinks >>>