Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

HIV reveals evolution of a primate defense against intragenomic infiltrators

20.07.2004


Published this week on-line in PLoS Biology, Sara Sawyer, Michael Emerman, and Harmit Malik investigate the genetic roots of the battle for evolutionary advantage between HIV-type viruses and the hosts they infect. What they find is surprising.


Antiviral editing enzymes like Apobec3G have been involved in an ancient genome defense strategy in primates



The gene, APOBEC3G, belongs to a family of primate genes that produce enzymes (in this case, APOBEC3G) that "edit" DNA and RNA, by slipping into viral particles and inducing mutations that replace one base (cytosine) with another (uracil) as the virus undergoes reverse transcription in the host cell’s cytoplasm. The edited virus fails to replicate. HIV, in turn, generates a protein called Vif that binds to the APOBEC3G enzyme and targets it for degradation, thereby eliminating its antiviral activity.

Since the protein-binding regions that govern these interactions have a direct effect on the fitness of both virus and host, one would expect to see the proteins angling for advantage, with Vif maximizing its ability to recognize APOBEC3G and APOBEC3G doing its best to evade Vif. Such battles are thought to result in frequent mutations that alter the amino acids involved in the interaction; the perpetuation of such advantageous mutations is called positive selection.


As predicted, the APOBEC3G gene is under strong positive selection. But that selection – characterized by an analysis of twelve primates species spanning 33 million years of evolution - appears to predate the existence of HIV-type viruses. So, what has been fueling APOBEC3G’s rapid evolution?

APOBEC3G and Vif interact in T-cells, but the fact that selective pressure on APOBEC3G has been constant over the course of primate evolution suggests that another force is also acting on the gene. Sawyer et al. propose that this force is exerted by human endogenous retroviruses, which act in many ways like foreign retroviruses. These mobile genetic elements emanating from one’s own genome pose less of an immediate threat than a retrovirus like HIV. But the constant efforts of the endogenous retrovirus to "jockey for evolutionary dominance," the authors conclude, could eventually take a toll and would be expected to provoke efforts to contain it. And it may be that this ancient intragenomic conflict endowed APOBEC3G with the means to do battle with foreign retroviruses like HIV. Therefore, despite being only recently discovered, editing of RNA and DNA may represent an ancient form of host defense in primate genomes.

Catriona MacCallum | EurekAlert!
Further information:
http://www.plos.org
http://www.plosbiology.org

More articles from Life Sciences:

nachricht Switch-in-a-cell electrifies life
18.12.2018 | Rice University

nachricht Plant biologists identify mechanism behind transition from insect to wind pollination
18.12.2018 | University of Toronto

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Data storage using individual molecules

Researchers from the University of Basel have reported a new method that allows the physical state of just a few atoms or molecules within a network to be controlled. It is based on the spontaneous self-organization of molecules into extensive networks with pores about one nanometer in size. In the journal ‘small’, the physicists reported on their investigations, which could be of particular importance for the development of new storage devices.

Around the world, researchers are attempting to shrink data storage devices to achieve as large a storage capacity in as small a space as possible. In almost...

Im Focus: Data use draining your battery? Tiny device to speed up memory while also saving power

The more objects we make "smart," from watches to entire buildings, the greater the need for these devices to store and retrieve massive amounts of data quickly without consuming too much power.

Millions of new memory cells could be part of a computer chip and provide that speed and energy savings, thanks to the discovery of a previously unobserved...

Im Focus: An energy-efficient way to stay warm: Sew high-tech heating patches to your clothes

Personal patches could reduce energy waste in buildings, Rutgers-led study says

What if, instead of turning up the thermostat, you could warm up with high-tech, flexible patches sewn into your clothes - while significantly reducing your...

Im Focus: Lethal combination: Drug cocktail turns off the juice to cancer cells

A widely used diabetes medication combined with an antihypertensive drug specifically inhibits tumor growth – this was discovered by researchers from the University of Basel’s Biozentrum two years ago. In a follow-up study, recently published in “Cell Reports”, the scientists report that this drug cocktail induces cancer cell death by switching off their energy supply.

The widely used anti-diabetes drug metformin not only reduces blood sugar but also has an anti-cancer effect. However, the metformin dose commonly used in the...

Im Focus: New Foldable Drone Flies through Narrow Holes in Rescue Missions

A research team from the University of Zurich has developed a new drone that can retract its propeller arms in flight and make itself small to fit through narrow gaps and holes. This is particularly useful when searching for victims of natural disasters.

Inspecting a damaged building after an earthquake or during a fire is exactly the kind of job that human rescuers would like drones to do for them. A flying...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

ICTM Conference 2019: Digitization emerges as an engineering trend for turbomachinery construction

12.12.2018 | Event News

New Plastics Economy Investor Forum - Meeting Point for Innovations

10.12.2018 | Event News

EGU 2019 meeting: Media registration now open

06.12.2018 | Event News

 
Latest News

Pressure tuned magnetism paves the way for novel electronic devices

18.12.2018 | Materials Sciences

New type of low-energy nanolaser that shines in all directions

18.12.2018 | Physics and Astronomy

NASA research reveals Saturn is losing its rings at 'worst-case-scenario' rate

18.12.2018 | Physics and Astronomy

VideoLinks
Science & Research
Overview of more VideoLinks >>>