Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Jumping gene could provide non-viral alternative for gene therapy

27.09.2006
A jumping gene first identified in a cabbage-eating moth may one day provide a safer, target-specific alternative to viruses for gene therapy, researchers say.

They compared the ability of the four best-characterized jumping genes, or transposons, to insert themselves into a cell's DNA and produce a desired change, such as making the cell resistant to damage from radiation therapy.

They found the piggyBac transposon was five to 10 times better than the other circular pieces of DNA at making a home and a difference in several mammalian cell lines, including three human ones.

"If we want to add a therapeutic gene, we can put it within the transposon and use it to deliver the gene into the cell," says Dr. Joseph M. Kaminski, radiation oncologist at the Medical College of Georgia Cancer Center and a corresponding author on research published the week of Sept. 25 in the online Proceedings of the National Academy of Sciences Early Edition. "You can use these wherever retroviruses have been used."

... more about:
»Beauty »DNA »piggyBac »retroviruses

In addition to piggyBac, researchers looked at what was believed to be the most efficient transposon in mammalian cells, hyperactive Sleeping Beauty, first found "asleep" in fish. They also looked at Tol2, another fish transposon, and Mos1, found in insects.

The piggyBac transposon, which has close relatives in the human genome, is widely used to genetically modify insects. Sleeping Beauty has been used to correct hereditary diseases, including hemophilia, in a mouse model.

For this study, researchers used transposons to deliver an antibiotic-resistant gene. "It's a way of screening and seeing which transposon is better," Dr. Kaminski says. They found that while piggyBac might not work as efficiently as a virus, it put Sleeping Beauty to shame when it came to making cells antibiotic-resistant.

"Sleeping Beauty has captured the field as far as transposons to be used in mammals," says Dr. Stefan Moisyadi, molecular biologist, at the University of Hawaii and a corresponding author. "But by comparing different transposons, we showed Sleeping Beauty is far inferior to piggyBac."

Scientists have used viruses as a gene delivery mechanism for more than 20 years because of their adeptness at getting inside cells and inserting themselves in DNA. But efficiency comes at a price. Gene therapy trials have been halted because of major complications, including deaths. As examples, one patient died because of his immune response to an adenovirus and three children in another study developed leukemia because the virus inserted itself upstream of a cancer-causing gene.

"With viruses, you don't have control," says Dr. Kaminski. "People have tried to modify viruses for site-specific integration and have not been very successful. Once they get into the cell, they can insert wherever they want."

Dr. Kaminski's previous work, published in 2002 in The FASEB Journal, hypothesized that the integration site for transposons can be selected. "Typically, viruses and transposons will integrate anywhere along the genome," he says. "If they integrate anywhere, it can obviously cause harm. If we can target the integration, be able to insert the gene at a safe spot in the genome, that would be beneficial." He confirmed that targeting integration is possible in a paper he co-authored in 2005 also in The FASEB Journal. "We can do it in insects," says Dr. Moisyadi. "I think it's a short step to take it to a targeting mechanism we can use in humans."

Another clear benefit is that transposons are cheaper to produce and probably safer than viruses. For example, retroviruses use RNA to make DNA, an error-prone process that must occur before integration, Dr. Kaminski says. Also, viruses can't carry larger genes, such as the dystrophin gene, which could help correct muscular dystrophy. On the other hand, unlike retroviruses, transposons have to be coated with lipid to slip into cells.

Although piggyBac is not as successful as the virus at integrating into DNA, "we could potentially make a hyperactive version of piggyBac, like they did for Sleeping Beauty, which might be as good or better than retroviruses," Dr. Kaminski says. "I think we'll do it or somebody will. I think it's a safer method."

"At the moment, unless something new comes out, it's the only way to go because viruses have been killing people," says Dr. Moisyadi, who has avoided viruses in his transgenesis studies.

"One of our next goals is to use transposons to deliver a radio-protective gene, called manganese superoxide dismutase, to potentially protect normal tissue from radiation damage," Dr. Kaminski says.

In cancer, he suspects gene therapy will focus on this type of modification of normal tissue for protective purposes as well as manipulating the immune response. However, it has broad applications for correcting single gene disorders, such as hemophilia, sickle cell disease and muscular dystrophy.

Toni Baker | EurekAlert!
Further information:
http://www.mcg.edu

Further reports about: Beauty DNA piggyBac retroviruses

More articles from Life Sciences:

nachricht Rainbow colors reveal cell history: Uncovering β-cell heterogeneity
22.09.2017 | DFG-Forschungszentrum für Regenerative Therapien TU Dresden

nachricht The pyrenoid is a carbon-fixing liquid droplet
22.09.2017 | Max-Planck-Institut für Biochemie

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: The pyrenoid is a carbon-fixing liquid droplet

Plants and algae use the enzyme Rubisco to fix carbon dioxide, removing it from the atmosphere and converting it into biomass. Algae have figured out a way to increase the efficiency of carbon fixation. They gather most of their Rubisco into a ball-shaped microcompartment called the pyrenoid, which they flood with a high local concentration of carbon dioxide. A team of scientists at Princeton University, the Carnegie Institution for Science, Stanford University and the Max Plank Institute of Biochemistry have unravelled the mysteries of how the pyrenoid is assembled. These insights can help to engineer crops that remove more carbon dioxide from the atmosphere while producing more food.

A warming planet

Im Focus: Highly precise wiring in the Cerebral Cortex

Our brains house extremely complex neuronal circuits, whose detailed structures are still largely unknown. This is especially true for the so-called cerebral cortex of mammals, where among other things vision, thoughts or spatial orientation are being computed. Here the rules by which nerve cells are connected to each other are only partly understood. A team of scientists around Moritz Helmstaedter at the Frankfiurt Max Planck Institute for Brain Research and Helene Schmidt (Humboldt University in Berlin) have now discovered a surprisingly precise nerve cell connectivity pattern in the part of the cerebral cortex that is responsible for orienting the individual animal or human in space.

The researchers report online in Nature (Schmidt et al., 2017. Axonal synapse sorting in medial entorhinal cortex, DOI: 10.1038/nature24005) that synapses in...

Im Focus: Tiny lasers from a gallery of whispers

New technique promises tunable laser devices

Whispering gallery mode (WGM) resonators are used to make tiny micro-lasers, sensors, switches, routers and other devices. These tiny structures rely on a...

Im Focus: Ultrafast snapshots of relaxing electrons in solids

Using ultrafast flashes of laser and x-ray radiation, scientists at the Max Planck Institute of Quantum Optics (Garching, Germany) took snapshots of the briefest electron motion inside a solid material to date. The electron motion lasted only 750 billionths of the billionth of a second before it fainted, setting a new record of human capability to capture ultrafast processes inside solids!

When x-rays shine onto solid materials or large molecules, an electron is pushed away from its original place near the nucleus of the atom, leaving a hole...

Im Focus: Quantum Sensors Decipher Magnetic Ordering in a New Semiconducting Material

For the first time, physicists have successfully imaged spiral magnetic ordering in a multiferroic material. These materials are considered highly promising candidates for future data storage media. The researchers were able to prove their findings using unique quantum sensors that were developed at Basel University and that can analyze electromagnetic fields on the nanometer scale. The results – obtained by scientists from the University of Basel’s Department of Physics, the Swiss Nanoscience Institute, the University of Montpellier and several laboratories from University Paris-Saclay – were recently published in the journal Nature.

Multiferroics are materials that simultaneously react to electric and magnetic fields. These two properties are rarely found together, and their combined...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

“Lasers in Composites Symposium” in Aachen – from Science to Application

19.09.2017 | Event News

I-ESA 2018 – Call for Papers

12.09.2017 | Event News

EMBO at Basel Life, a new conference on current and emerging life science research

06.09.2017 | Event News

 
Latest News

Rainbow colors reveal cell history: Uncovering β-cell heterogeneity

22.09.2017 | Life Sciences

Penn first in world to treat patient with new radiation technology

22.09.2017 | Medical Engineering

Calculating quietness

22.09.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>