Corporate Banner
Satellite Banner
Scientific Communities
Become a Member | Sign in
Home>News>This Article

Cheap and Easy Technique to Snip DNA Could Revolutionize Gene Therapy

Published: Tuesday, January 08, 2013
Last Updated: Tuesday, January 08, 2013
Bookmark and Share
A simple, precise and inexpensive method for cutting DNA to insert genes into human cells could transform genetic medicine.

Method could make routine what now are expensive, complicated and rare procedures for replacing defective genes in order to fix genetic disease or even cure AIDS.

Discovered last year by Jennifer Doudna and Martin Jinek of the Howard Hughes Medical Institute and University of California, Berkeley, and Emmanuelle Charpentier of the Laboratory for Molecular Infection Medicine-Sweden, the technique was labeled a “tour de force” in a 2012 review in the journal Nature Biotechnology.

That review was based solely on the team’s June 28, 2012, Science paper, in which the researchers described a new method of precisely targeting and cutting DNA in bacteria.

Two new papers published last week in the journal Science Express demonstrate that the technique also works in human cells. A paper by Doudna and her team reporting similarly successful results in human cells has been accepted for publication by the new open-access journal eLife.

“The ability to modify specific elements of an organism’s genes has been essential to advance our understanding of biology, including human health,” said Doudna, a professor of molecular and cell biology and of chemistry and a Howard Hughes Medical Institute Investigator at UC Berkeley. “However, the techniques for making these modifications in animals and humans have been a huge bottleneck in both research and the development of human therapeutics.

“This is going to remove a major bottleneck in the field, because it means that essentially anybody can use this kind of genome editing or reprogramming to introduce genetic changes into mammalian or, quite likely, other eukaryotic systems.”

“I think this is going to be a real hit,” said George Church, professor of genetics at Harvard Medical School and principal author of one of the Science Express papers. “There are going to be a lot of people practicing this method because it is easier and about 100 times more compact than other techniques.”

“Based on the feedback we’ve received, it’s possible that this technique will completely revolutionize genome engineering in animals and plants,” said Doudna, who also holds an appointment at Lawrence Berkeley National Laboratory. “It’s easy to program and could potentially be as powerful as the Polymerase Chain Reaction (PCR).”

The latter technique made it easy to generate millions of copies of small pieces of DNA and permanently altered biological research and medical genetics.

Cruise missiles

Two developments – zinc-finger nucleases and TALEN (Transcription Activator-Like Effector Nucleases) proteins – have gotten a lot of attention recently, including being together named one of the top 10 scientific breakthroughs of 2012 by Science magazine. The magazine labeled them “cruise missiles” because both techniques allow researchers to home in on a particular part of a genome and snip the double-stranded DNA there and there only.

Researchers can use these methods to make two precise cuts to remove a piece of DNA and, if an alternative piece of DNA is supplied, the cell will plug it into the cut instead. In this way, doctors can excise a defective or mutated gene and replace it with a normal copy. Sangamo Biosciences, a clinical stage biospharmaceutical company, has already shown that replacing one specific gene in a person infected with HIV can make him or her resistant to AIDS.

Both the zinc finger and TALEN techniques require synthesizing a large new gene encoding a specific protein for each new site in the DNA that is to be changed. By contrast, the new technique uses a single protein that requires only a short RNA molecule to program it for site-specific DNA recognition, Doudna said.

In the new Science Express paper, Church compared the new technique, which involves an enzyme called Cas9, with the TALEN method for inserting a gene into a mammalian cell and found it five times more efficient.

“It (the Cas9-RNA complex) is easier to make than TALEN proteins, and it’s smaller,” making it easier to slip into cells and even to program hundreds of snips simultaneously, he said. The complex also has lower toxicity in mammalian cells than other techniques, he added.
“It’s too early to declare total victory” over TALENs and zinc-fingers, Church said, “but it looks promising.”

Based on the immune systems of bacteria

Doudna discovered the Cas9 enzyme while working on the immune system of bacteria that have evolved enzymes that cut DNA to defend themselves against viruses. These bacteria cut up viral DNA and stick pieces of it into their own DNA, from which they make RNA that binds and inactivates the viruses.

UC Berkeley professor of earth and planetary science Jill Banfield brought this unusual viral immune system to Doudna’s attention a few years ago, and Doudna became intrigued. Her research focuses on how cells use RNA (ribonucleic acids), which are essentially the working copies that cells make of the DNA in their genes.

Doudna and her team worked out the details of how the enzyme-RNA complex cuts DNA: the Cas9 protein assembles with two short lengths of RNA, and together the complex binds a very specific area of DNA determined by the RNA sequence. The scientists then simplified the system to work with only one piece of RNA and showed in the earlier Science paper that they could target and snip specific areas of bacterial DNA.

“The beauty of this compared to any of the other systems that have come along over the past few decades for doing genome engineering is that it uses a single enzyme,” Doudna said. “The enzyme doesn’t have to change for every site that you want to target – you simply have to reprogram it with a different RNA transcript, which is easy to design and implement.”

The three new papers show this bacterial system works beautifully in human cells as well as in bacteria.

“Out of this somewhat obscure bacterial immune system comes a technology that has the potential to really transform the way that we work on and manipulate mammalian cells and other types of animal and plant cells,” Doudna said. “This is a poster child for the role of basic science in making fundamental discoveries that affect human health.”

Further Information
Access to this exclusive content is for Technology Networks Premium members only.

Join Technology Networks Premium for free access to:

  • Exclusive articles
  • Presentations from international conferences
  • Over 2,800+ scientific posters on ePosters
  • More Than 4,000+ scientific videos on LabTube
  • 35 community eNewsletters

Sign In

Forgotten your details? Click Here
If you are not a member you can join here

*Please note: By logging into you agree to accept the use of cookies. To find out more about the cookies we use and how to delete them, see our privacy policy.

Related Content

Modelling the Early Human Heart
Researchers have developed a template for growing beating cardiac tissue from stem cells, creating a system that could serve as a model for early heart development and as a drug-screening tool to make pregnancies safer.
Wednesday, July 15, 2015
Smartphone Video Microscope Automates Detection Of Parasites In Blood
A mobile phone-based video microscope developed by a UC Berkeley-led team, is as good as conventional blood smears in detecting levels of the Loa loa parasitic worm.
Monday, May 11, 2015
Hearts On A Chip To Aid Drug Screening
UC Berkeley bioengineers have developed a heart-on-a-chip which can be used for drug safety screening.
Monday, March 09, 2015
Innovative Genomics Initiative Launched
Launch of new genomics initiative draws enthusiastic industry, academic partners.
Friday, February 06, 2015
Grapefruit Juice Stems Weight Gain in Mice Fed a High-Fat Diet
A study from UC Berkeley found that mice fed a high-fat diet gained 18% less weight when they drank clarified, pulp-free grapefruit juice compared with a control group of mice that drank water.
Friday, October 10, 2014
Polar Bear Genome Gives New Insight Into Adaptations to High-fat Diet
A comparison of the genomes of polar bears and brown bears reveals that the polar bear is a much younger species than previously believed, having diverged from brown bears less than 500,000 years ago.
Thursday, May 15, 2014
UC Berkeley, UCSF Launch Innovative Genomics Initiative
Li Ka Shing Foundation provides $10M gift to support the initiative, establishing the Li Ka Shing Center for Genomic Engineering and an affiliated faculty chair at UC Berkeley.
Tuesday, March 18, 2014
Alivisatos appointed Samsung Distinguished Chair in Nanoscience
Chemist Paul Alivisatos awarded appointment UC Berkeley in recognition of his many scientific achievements.
Friday, August 23, 2013
Air Pollution Study Clears the Air on Diesel Versus Gas Emissions
Diesel exhaust contributes 15 times more than gas emissions per liter of fuel burned, new study reports.
Thursday, October 25, 2012
Contaminated Site Yields Wealth of Information on Microbes 10 Feet Under
Sequencing of nearly 150,000 genes from soil samples at a former uranium mill site along the Colorado River in Rifle, Colo.
Thursday, October 04, 2012
NSF Awards $3.4 Million to Train Students in “Green Chemistry”
BCGC wins $3.4 million NSF training grant: Grad students encouraged to apply.
Wednesday, September 12, 2012
In Mice, Having Multiple Partners Breeds More Robust Immune System
UC Berkeley researchers use TACC's Ranger supercomputer to identify genetic differences related to the social lives of mammals.
Wednesday, September 12, 2012
Scientific News
High Throughput Mass Spectrometry-Based Screening Assay Trends
Dr John Comley provides an insight into HT MS-based screening with a focus on future user requirements and preferences.
How a Genetic Locus Protects Adult Blood-Forming Stem Cells
Mammalian imprinted Gtl2 protects adult hematopoietic stem cells by restricting metabolic activity in the cells' mitochondria.
Genetic Basis of Fatal Flu Side Effect Discovered
A group of people with fatal H1N1 flu died after their viral infections triggered a deadly hyperinflammatory disorder in susceptible individuals with gene mutations linked to the overactive immune response, according to a recent study.
New Tech Vastly Improves CRISPR/Cas9 Accuracy
A new CRISPR/Cas9 technology developed by scientists at UMass Medical School is precise enough to surgically edit DNA at nearly any genomic location, while avoiding potentially harmful off-target changes typically seen in standard CRISPR gene editing techniques.
The MaxSignal Colistin ELISA Test Kit from Bioo Scientific
Kit can help prevent the antibiotic apocalypse by keeping last resort drugs out of the food supply.
"Good" Mozzie Virus Might Hold Key to Fighting Human Disease
Australian scientists have discovered a new virus carried by one of the country’s most common pest mosquitoes.
Non-Disease Proteins Kill Brain Cells
Scientists at the forefront of cutting-edge research into neurodegenerative diseases such as Alzheimer’s and Parkinson’s have shown that the mere presence of protein aggregates may be as important as their form and identity in inducing cell death in brain tissue.
Closing the Loop on an HIV Escape Mechanism
Research team finds that protein motions regulate virus infectivity.
New Class of RNA Tumor Suppressors Identified
Two short, “housekeeping” RNA molecules block cancer growth by binding to an important cancer-associated protein called KRAS. More than a quarter of all human cancers are missing these RNAs.
Potential Treatment for Life-Threatening Viral Infections Revealed
The findings point to new therapies for Dengue, West Nile and Ebola.
Scroll Up
Scroll Down
Skyscraper Banner

Skyscraper Banner
Go to LabTube
Go to eposters
Access to the latest scientific news
Exclusive articles
Upload and share your posters on ePosters
Latest presentations and webinars
View a library of 1,800+ scientific and medical posters
2,800+ scientific and medical posters
A library of 2,500+ scientific videos on LabTube
4,000+ scientific videos