Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Stolen gene allows insect virus to enter cells

04.07.2005


A gene enabling an insect virus to enter new cells was likely stolen from a host cell and adapted for the virus’s use, researchers at Boyce Thompson Institute (BTI) at Cornell University report.



Virologists have long thought of baculoviruses, a group of viruses that can liquefy their insect hosts in a matter of days but don’t induce so much as a sneeze in mammals, as potential pesticides. But the viruses would require tweaking to be effective since they kill insects more slowly than chemical insecticides. Studying baculoviruses also yields insights into general viral behavior. The current study examined how baculoviruses took the evolutionary leap needed to become the nasty bugs they are today.

In the study, reported in the July 1 issue of the Journal of Virology, BTI researchers Gary Blissard and Oliver Lung investigated whether a fruit fly gene, called an f gene, had originally moved from an insect to a virus or the other way around. (Retroviruses, such as HIV, insert their own genes into their hosts’ DNA in order to replicate, and remnants of these invaders can be passed to descendants.) In viruses, an f gene codes for a fusion (F) protein, which enables the virus to penetrate the host cell’s membrane and infect it. Scientists had shown that some other viral genes were probably copied from host cells, but the origin of so-called fusion proteins, like F, has remained a mystery.


"The gigantic step was when the Drosophila melanogaster [fruit fly] genome was published," Blissard says. "The first thing was to ask whether the gene was turned on or not, to validate whether it’s a bona fide gene."

Blissard and Lung found messenger RNA (mRNA) copies of the gene in fruit fly cells, as well as F proteins--both products unlikely to arise if f were a piece of "junk DNA" left over from a long-departed retrovirus. The researchers then looked for evidence that the fruit fly regulates the f gene, switching it on and off as needed. Indeed, they found that the f gene stays quiet until the third and final stage of a maggot’s development, then begins to produce F proteins, which persist into adulthood. "f seems to be developmentally regulated, like a lot of Drosophila genes," says Blissard. Exactly what role the F protein plays in fruit flies remains to be answered.

At some point, perhaps after retroviruses had sprinkled host genomes with multiple copies of the f gene, a baculovirus picked it up through recombination. Unlike retroviruses, baculoviruses don’t insert their genes into their hosts’ genomes. They do steal genes, however, by mixing host DNA with their own. "The way they generate diversity in their genome is by recombination," Blissard says.

No matter how the original f gene moved from the fruit fly into viruses, it had to change a lot to win its current starring role in infectivity, Blissard says. He and Lung found that while viral F proteins naturally migrate to the surface of a host cell, F proteins native to the cell appear to stay on the inside. "Membrane fusion goes on all over the place inside the cell," Blissard says. "But fusion in cells is regulated by fairly large complexes of proteins. Viruses can accomplish membrane fusion with a one-protein machine." The F in fruit flies may not even be a fusion protein.

If the F protein is so important, how did baculoviruses get along without it? These viruses actually generate two types of infectious particles, Blissard explains: one type specialized to infect gut cells, and another that spreads infection in other parts of the insect. The latter type uses F to enter cells. An ancestor of today’s baculoviruses "might have just existed as a diarrheal-type virus, reproducing itself at a low level in the gut, letting the host survive," Blissard hypothesizes. "Picking up the f gene may have caused a radical change in the pathology of this virus, because a virus that co-exists nicely with its host will function a lot differently than one that’s trying to use all the tissues of the animal." In other words, it might have been a host’s own gene that turned baculoviruses into the lean, mean killing machines they are today.

The study was funded by the National Institutes of Health and the Boyce Thompson Institute for Plant Research.

Shawna Williams | EurekAlert!
Further information:
http://www.cornell.edu

More articles from Life Sciences:

nachricht Cryo-electron microscopy achieves unprecedented resolution using new computational methods
24.03.2017 | DOE/Lawrence Berkeley National Laboratory

nachricht How cheetahs stay fit and healthy
24.03.2017 | Forschungsverbund Berlin e.V.

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Giant Magnetic Fields in the Universe

Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.

The results will be published on March 22 in the journal „Astronomy & Astrophysics“.

Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...

Im Focus: Tracing down linear ubiquitination

Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.

Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...

Im Focus: Perovskite edges can be tuned for optoelectronic performance

Layered 2D material improves efficiency for solar cells and LEDs

In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...

Im Focus: Polymer-coated silicon nanosheets as alternative to graphene: A perfect team for nanoelectronics

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...

Im Focus: Researchers Imitate Molecular Crowding in Cells

Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to simulate these confined natural conditions in artificial vesicles for the first time. As reported in the academic journal Small, the results are offering better insight into the development of nanoreactors and artificial organelles.

Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

International Land Use Symposium ILUS 2017: Call for Abstracts and Registration open

20.03.2017 | Event News

CONNECT 2017: International congress on connective tissue

14.03.2017 | Event News

ICTM Conference: Turbine Construction between Big Data and Additive Manufacturing

07.03.2017 | Event News

 
Latest News

Argon is not the 'dope' for metallic hydrogen

24.03.2017 | Materials Sciences

Astronomers find unexpected, dust-obscured star formation in distant galaxy

24.03.2017 | Physics and Astronomy

Gravitational wave kicks monster black hole out of galactic core

24.03.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>