Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

New genome-editing platform significantly increases accuracy of CRISPR-based systems

28.04.2014

A next-generation genome editing system developed by Massachusetts General Hospital (MGH) investigators substantially decreases the risk of producing unwanted, off-target gene mutations.

In a paper receiving online publication in Nature Biotechnology, the researchers report a new CRISPR-based RNA-guided nuclease technology that uses two guide RNAs, significantly reducing the chance of cutting through DNA strands at mismatched sites.

"This system combines the ease of use of the widely adopted CRISPR/Cas system with a dimerization-dependent nuclease activity that confers higher specificity of action," says J. Keith Joung, MD, PhD, associate chief for Research in the MGH Department of Pathology and senior author of the report. "Higher specificity will be essential for any future clinical use of these nucleases, and the new class of proteins we describe could provide an important option for therapeutic genome editing."

Engineered CRISPR-Cas nucleases – genome-editing tools that combine a short RNA segment matching its DNA target with a DNA-cutting enzyme called Cas9 – have been the subject of much investigation since their initial development in 2012.

Easier to use than the earlier ZFN (zinc finger nuclease) and TALEN (transcription activator-like effector nuclease) systems, they have successfully induced genomic changes in several animal models systems and in human cells. But in a previous Nature Biotechnology paper published in June 2013, Joung's team reported that CRISPR-Cas nucleases could produce additional mutations in human cells, even at sites that differed from the DNA target by as much as five nucleotides.

To address this situation, the investigators developed a new platform in which the targeting function of Cas9 was fused to a nuclease derived from a well-characterized enzyme called Fokl, which only functions when two copies of the molecule are paired, a relationship called dimerization.

This change essentially doubled the length of DNA that must be recognized for cleavage by these new CRISPR RNA-guided Fokl nucleases (RFNs), significantly increasing the precision of genome editing in human cells. Importantly, Joung and his colleagues also demonstrated that these new RFNs are as effective at on-target modification as existing Cas9 nucleases that target a shorter DNA sequence.

"By doubling the length of the recognized DNA sequence, we have developed a new class of genome -editing tools with substantially improved fidelity compared with existing wild-type Cas9 nucleases and nickases (enzymes that cleave a single DNA strand)," says Joung, an associate professor of Pathology at Harvard Medical School. The research team also has developed software enabling users to identify potential target sites for these RFNs and incorporated that capability into ZiFiT Targeter, a software package freely available at http://zifit.partners.org.

###

Lead author of the Nature Biotechnology report is Shengdar Tsai, PhD, of the MGH Molecular Pathology Unit. Additional co-authors are Nicolas Wyvekens, Cyd Khayter, Jennifer Foden, Vishal Thapar, Deepak Reyon, PhD, Mathew Goodwin and Martin Aryee, PhD, all of MGH Molecular Pathology. The study was supported by National Institutes of Health Director's Pioneer Award DP1 GM105378; NIH grants R01 GM088040, P50 HG005550, and R01 AR063070; and by the Jim and Ann Orr Massachusetts General Hospital MGH Research Scholar Award. Joung is a co-founder of Editas Medicine, Inc., which has an exclusive option to license the new CRISPR RNA-guided Fokl nuclease technology for therapeutic applications.

Massachusetts General Hospital, founded in 1811, is the original and largest teaching hospital of Harvard Medical School. The MGH conducts the largest hospital-based research program in the United States, with an annual research budget of more than $775 million and major research centers in AIDS, cardiovascular research, cancer, computational and integrative biology, cutaneous biology, human genetics, medical imaging, neurodegenerative disorders, regenerative medicine, reproductive biology, systems biology, transplantation biology and photomedicine.

Sue McGreevey | Eurek Alert!

Further reports about: Biotechnology CRISPR DNA MGH Pathology RNA-guided enzyme sequence therapeutic

More articles from Life Sciences:

nachricht From rigid to flexible
29.08.2016 | Technische Universität Dresden

nachricht Moth takes advantage of defensive compounds in Physalis fruits
26.08.2016 | Max-Planck-Institut für chemische Ökologie

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Streamlining accelerated computing for industry

PyFR code combines high accuracy with flexibility to resolve unsteady turbulence problems

Scientists and engineers striving to create the next machine-age marvel--whether it be a more aerodynamic rocket, a faster race car, or a higher-efficiency jet...

Im Focus: X-ray optics on a chip

Waveguides are widely used for filtering, confining, guiding, coupling or splitting beams of visible light. However, creating waveguides that could do the same for X-rays has posed tremendous challenges in fabrication, so they are still only in an early stage of development.

In the latest issue of Acta Crystallographica Section A: Foundations and Advances , Sarah Hoffmann-Urlaub and Tim Salditt report the fabrication and testing of...

Im Focus: Piggyback battery for microchips: TU Graz researchers develop new battery concept

Electrochemists at TU Graz have managed to use monocrystalline semiconductor silicon as an active storage electrode in lithium batteries. This enables an integrated power supply to be made for microchips with a rechargeable battery.

Small electrical gadgets, such as mobile phones, tablets or notebooks, are indispensable accompaniments of everyday life. Integrated circuits in the interiors...

Im Focus: UCI physicists confirm possible discovery of fifth force of nature

Light particle could be key to understanding dark matter in universe

Recent findings indicating the possible discovery of a previously unknown subatomic particle may be evidence of a fifth fundamental force of nature, according...

Im Focus: Wi-fi from lasers

White light from lasers demonstrates data speeds of up to 2 GB/s

A nanocrystalline material that rapidly makes white light out of blue light has been developed by KAUST researchers.

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

The energy transition is not possible without Geotechnics

25.08.2016 | Event News

New Ideas for the Shipping Industry

24.08.2016 | Event News

A week of excellence: 22 of the world’s best computer scientists and mathematicians in Heidelberg

12.08.2016 | Event News

 
Latest News

3-D-printed structures 'remember' their shapes

29.08.2016 | Materials Sciences

From rigid to flexible

29.08.2016 | Life Sciences

Sensor systems identify senior citizens at risk of falling within 3 weeks

29.08.2016 | Medical Engineering

VideoLinks
B2B-VideoLinks
More VideoLinks >>>