Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Stanford scientists flick genetic switch; may lead to new disease treatments

04.07.2002


Genes that are inappropriately turned on play a critical role in triggering some diseases. For researchers, the trick is learning how to deactivate these genes to treat illnesses. In a step toward reaching that goal, scientists at Stanford University Medical Center have developed a gene-therapy technique to switch off genes in mice. The finding could potentially lead to ways of treating such diseases as cancer, hepatitis C and AIDS.



In plants and lower organisms such as flies or worms, researchers can experimentally switch off genes by inserting RNA. Genes normally produce RNA molecules, which the cell uses as a template to create proteins. The injected RNA interferes with the usual order of events and prevents protein from being made - effectively shutting down the gene.

"RNA inhibition has been shown to work in lower organisms, but there was some question about whether it would work in mammals," said Mark Kay, MD, PhD, professor of genetics and pediatrics at Stanford.


Initial attempts to use RNA inhibition in mice were unsuccessful, but when Anton McCaffrey, PhD, joined Kay’s lab as a postdoctoral fellow he decided to give RNA inhibition another chance. His results will be published in the July 4 issue of Nature.

To observe the RNA inhibition process, McCaffrey injected mice with a firefly gene called luciferase that makes a light-producing protein. In half the mice, he also injected RNA that inhibits luciferase production. In mice receiving both luciferase and the RNA, whole-body scans showed 80 percent to 90 percent less light compared to mice that received the luciferase gene alone.

In a related experiment, McCaffrey hooked the luciferase gene to a small part of a gene from the hepatitis C virus and injected the hybrid gene into mice along with RNA that is specific to the DNA found in hepatitis C. Once again, mice that received both the gene and the RNA produced significantly less light than mice receiving only the luciferase gene. This experiment suggests that RNA inhibition could be used to deactivate genes from a virus such as hepatitis C or HIV, Kay said. By deactivating genes used by the virus to replicate, researchers could halt an infection in its tracks.

Kay added that although these results look promising, they rely on injected RNA. "RNA doesn’t last long in cells," he said. The problem is that in order for the RNA inhibition to work, two RNA molecules must be paired to form a double-stranded molecule. An easier approach would be to inject DNA, which is more durable than RNA, and have the DNA produce the proper RNA. Usual methods of injecting DNA, however, produce single-stranded RNA, which is useless for inhibition - a problem the scientists have worked to solve.

McCaffrey and Kay devised a way around this dilemma after consulting with a colleague. The team injected mice with a DNA molecule that produces an unusual RNA which doubles back on itself like a hairpin to make a single, double-stranded molecule. Injecting this novel RNA into mice was as effective at inhibiting the luciferase gene as injecting double-stranded RNA. What’s more, even after the hairpin RNA breaks down, the DNA remains in the cell and continues producing new RNA.

Kay said that this initial work is a proof of concept. "The ultimate goal is to use this to treat a disease," Kay said. "We can do this by placing these molecules into standard gene-therapy vectors." As examples, he said researchers could deactivate virus genes or genes involved in cancer. Kay added that methods of delivering DNA to cells are currently being tested and could potentially be used to provide RNA inhibition, staving off or even preventing some diseases.


Stanford University Medical Center integrates research, medical education and patient care at its three institutions - Stanford University School of Medicine, Stanford Hospital & Clinics and Lucile Packard Children’s Hospital at Stanford. For more information, please visit the Web site of the medical center’s Office of Communication & Public Affairs at http://mednews.stanford.edu.

Amy Adams | EurekAlert!
Further information:
http://mednews.stanford.edu
http://med-www.stanford.edu/MedCenter/MedSchool/

More articles from Life Sciences:

nachricht Closing in on advanced prostate cancer
13.12.2017 | Institute for Research in Biomedicine (IRB Barcelona)

nachricht Visualizing single molecules in whole cells with a new spin
13.12.2017 | Wyss Institute for Biologically Inspired Engineering at Harvard

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Long-lived storage of a photonic qubit for worldwide teleportation

MPQ scientists achieve long storage times for photonic quantum bits which break the lower bound for direct teleportation in a global quantum network.

Concerning the development of quantum memories for the realization of global quantum networks, scientists of the Quantum Dynamics Division led by Professor...

Im Focus: Electromagnetic water cloak eliminates drag and wake

Detailed calculations show water cloaks are feasible with today's technology

Researchers have developed a water cloaking concept based on electromagnetic forces that could eliminate an object's wake, greatly reducing its drag while...

Im Focus: Scientists channel graphene to understand filtration and ion transport into cells

Tiny pores at a cell's entryway act as miniature bouncers, letting in some electrically charged atoms--ions--but blocking others. Operating as exquisitely sensitive filters, these "ion channels" play a critical role in biological functions such as muscle contraction and the firing of brain cells.

To rapidly transport the right ions through the cell membrane, the tiny channels rely on a complex interplay between the ions and surrounding molecules,...

Im Focus: Towards data storage at the single molecule level

The miniaturization of the current technology of storage media is hindered by fundamental limits of quantum mechanics. A new approach consists in using so-called spin-crossover molecules as the smallest possible storage unit. Similar to normal hard drives, these special molecules can save information via their magnetic state. A research team from Kiel University has now managed to successfully place a new class of spin-crossover molecules onto a surface and to improve the molecule’s storage capacity. The storage density of conventional hard drives could therefore theoretically be increased by more than one hundred fold. The study has been published in the scientific journal Nano Letters.

Over the past few years, the building blocks of storage media have gotten ever smaller. But further miniaturization of the current technology is hindered by...

Im Focus: Successful Mechanical Testing of Nanowires

With innovative experiments, researchers at the Helmholtz-Zentrums Geesthacht and the Technical University Hamburg unravel why tiny metallic structures are extremely strong

Light-weight and simultaneously strong – porous metallic nanomaterials promise interesting applications as, for instance, for future aeroplanes with enhanced...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

See, understand and experience the work of the future

11.12.2017 | Event News

Innovative strategies to tackle parasitic worms

08.12.2017 | Event News

AKL’18: The opportunities and challenges of digitalization in the laser industry

07.12.2017 | Event News

 
Latest News

Gecko adhesion technology moves closer to industrial uses

13.12.2017 | Information Technology

Columbia engineers create artificial graphene in a nanofabricated semiconductor structure

13.12.2017 | Physics and Astronomy

Research reveals how diabetes in pregnancy affects baby's heart

13.12.2017 | Health and Medicine

VideoLinks
B2B-VideoLinks
More VideoLinks >>>