Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

HIV targets active genes in cells

23.08.2002


HIV selectively inserts itself into active areas of a host cell’s genome, Salk Institute researchers have found for the first time. The fact that the virus hooks itself up to areas of the cell’s genome that are busy expressing themselves may help explain why HIV can replicate, or reproduce itself, so rapidly. The findings are being published as the cover article in the Friday, August 23, issue of the journal Cell.



"HIV seems to be targeting not just genes, but active genes," said Salk researcher Frederic Bushman, a specialist in infectious diseases who headed the research team. "That makes a lot of biological sense if the targeting has evolved to promote efficient expression of the viral genome once it integrates into the cell."

The findings may have implications for developing more effective gene therapies, said Bushman, Associate Professor in the Infectious Disease Laboratory. Gene therapy involves treating genetic disorders by using a mutated retrovirus to insert a new gene into a defective genome. Gene therapy could be made safer and more effective by knowing more about and taking advantage of a retrovirus’s targeting specificity, he said.


Retroviruses like HIV reproduce themselves by infecting a cell, making a DNA copy of the virus’s RNA genome, and integrating that DNA copy into a chromosome of the host. When the genome of the host is "read" to produce proteins and gene products, so is the genome of the virus-which reproduces itself. The question Bushman and his team sought to answer was, where in the human chromosome does the virus integrate itself?

The team took advantage of the recently published human genome sequence. The researchers infected human cells in tissue culture with the HIV virus, and then broke open the cells and sequenced pieces of DNA to find out where the viral DNA ended up. By matching DNA segments with the published human genome sequence, they found that that the viral DNA mostly ended up in areas of the chromosomes where there are human genes, rather than places in between.

The researchers then asked, "What is it about these genes? Are they active genes, or is it something else about being a gene that’s good?" Using another new technology, gene chips that help screen for products made by active genes, the researchers found that the genes that were targeted were disproportionately active ones.

In fact, Bushman said, the genes that are targeted are specifically ones that are turned on by infection with HIV itself. When the virus enters a cell, it triggers a response by the cell that includes making new proteins in response to the infection. So in essence, the HIV virus wields a double-edged sword, creating a weakness and then taking advantage of it.

Most HIV-infected cells die relatively quickly, within a day or two, Bushman said, so it’s to the virus’s advantage to be able to reproduce quickly. "Viruses that integrate into different points of the human genome inside a cell replicate with very different efficiencies," Bushman said. "There are bad places to be, where it’s hard to express your genome, and there are other places where you can express very efficiently." HIV, it appears, is extremely efficient.

HIV differs from other types of genomic pathogens, Bushman said, that have evolved to live with their host on a long-term basis. These may target relatively benign regions of the genome where they don’t hurt the host, and they reproduce because the cells continue to live, grow and divide, reproducing the pathogen as the cell itself reproduces.

"Not so with HIV," Bushman said. "HIV has aggressive targeting. That targeting is damaging to the host, but for an aggressive parasite in a cell that’s only going to live for a day or so, it makes a sensible evolutionary strategy."


Other members of the research team included Salk researchers Astrid Shröder (the paper’s lead author), Paul Shinn, Huaming Chen, Charles Berry, and Joseph Ecker.

The Salk Institute for Biological Studies, located in La Jolla, Calif., is an independent nonprofit institution dedicated to fundamental discoveries in the life sciences, the improvement of human health and conditions, and the training of future generations of researchers. Jonas Salk, M.D., founded the Institute in 1960 with a gift of land from the City of San Diego and the financial support of the March of Dimes Birth Defects Foundation.

Kristin Bertell | EurekAlert!
Further information:
http://www.salk.edu/

More articles from Health and Medicine:

nachricht Custom-tailored strategy against glioblastomas
26.09.2016 | Rheinische Friedrich-Wilhelms-Universität Bonn

nachricht New leukemia treatment offers hope
23.09.2016 | King Abdullah University of Science and Technology

All articles from Health and Medicine >>>

The most recent press releases about innovation >>>

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

Im Focus: OLED microdisplays in data glasses for improved human-machine interaction

The Fraunhofer Institute for Organic Electronics, Electron Beam and Plasma Technology FEP has been developing various applications for OLED microdisplays based on organic semiconductors. By integrating the capabilities of an image sensor directly into the microdisplay, eye movements can be recorded by the smart glasses and utilized for guidance and control functions, as one example. The new design will be debuted at Augmented World Expo Europe (AWE) in Berlin at Booth B25, October 18th – 19th.

“Augmented-reality” and “wearables” have become terms we encounter almost daily. Both can make daily life a little simpler and provide valuable assistance for...

Im Focus: Artificial Intelligence Helps in the Discovery of New Materials

With the help of artificial intelligence, chemists from the University of Basel in Switzerland have computed the characteristics of about two million crystals made up of four chemical elements. The researchers were able to identify 90 previously unknown thermodynamically stable crystals that can be regarded as new materials. They report on their findings in the scientific journal Physical Review Letters.

Elpasolite is a glassy, transparent, shiny and soft mineral with a cubic crystal structure. First discovered in El Paso County (Colorado, USA), it can also be...

Im Focus: Complex hardmetal tools out of the 3D printer

For the first time, Fraunhofer IKTS shows additively manufactured hardmetal tools at WorldPM 2016 in Hamburg. Mechanical, chemical as well as a high heat resistance and extreme hardness are required from tools that are used in mechanical and automotive engineering or in plastics and building materials industry. Researchers at the Fraunhofer Institute for Ceramic Technologies and Systems IKTS in Dresden managed the production of complex hardmetal tools via 3D printing in a quality that are in no way inferior to conventionally produced high-performance tools.

Fraunhofer IKTS counts decades of proven expertise in the development of hardmetals. To date, reliable cutting, drilling, pressing and stamping tools made of...

Im Focus: Launch of New Industry Working Group for Process Control in Laser Material Processing

At AKL’16, the International Laser Technology Congress held in May this year, interest in the topic of process control was greater than expected. Appropriately, the event was also used to launch the Industry Working Group for Process Control in Laser Material Processing. The group provides a forum for representatives from industry and research to initiate pre-competitive projects and discuss issues such as standards, potential cost savings and feasibility.

In the age of industry 4.0, laser technology is firmly established within manufacturing. A wide variety of laser techniques – from USP ablation and additive...

Im Focus: New laser joining technologies at ‘K 2016’ trade fair

Every three years, the plastics industry gathers at K, the international trade fair for plastics and rubber in Düsseldorf. The Fraunhofer Institute for Laser Technology ILT will also be attending again and presenting many innovative technologies, such as for joining plastics and metals using ultrashort pulse lasers. From October 19 to 26, you can find the Fraunhofer ILT at the joint Fraunhofer booth SC01 in Hall 7.

K is the world’s largest trade fair for the plastics and rubber industry. As in previous years, the organizers are expecting 3,000 exhibitors and more than...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Experts from industry and academia discuss the future mobile telecommunications standard 5G

23.09.2016 | Event News

ICPE in Graz for the seventh time

20.09.2016 | Event News

Using mathematical models to understand our brain

16.09.2016 | Event News

 
Latest News

Stronger turbine blades with molybdenum silicides

26.09.2016 | Materials Sciences

Scientists Find Twisting 3-D Raceway for Electrons in Nanoscale Crystal Slices

26.09.2016 | Materials Sciences

Lowering the Heat Makes New Materials Possible While Saving Energy

26.09.2016 | Materials Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>