Featured Research

from universities, journals, and other organizations

Imaging study shows HIV particles assembling around genome of infected cell

Date:
January 2, 2010
Source:
Rockefeller University
Summary:
HIV is a wily and lethal replicator. In less than 25 years, it's killed more than 25 million people. Scientists are exploring exactly how this virus reproduces because they would like to find a way to abort the process. Now, just two years after scientists witnessed the birth of a single HIV particle in real time, the same team has zoomed in for a closer look at how the virus packages its genetic material as it assembles beneath the surface of an infected cell.

Bound by Gag. New imaging experiments show that individual HIV genomes (green) dock at the cell membrane in an early stage of new HIV particle formation. As HIV structural proteins called Gag (red) assemble around the genomes, the complex of the two turns yellow.
Credit: Image courtesy of Rockefeller University

HIV is a wily and lethal replicator. In less than 25 years, it's killed more than 25 million people. Scientists are exploring exactly how this virus reproduces because they would like to find a way to abort the process. Now, just two years after a group at Rockefeller University was the first to witness the birth of a single HIV particle in real time, the same team has zoomed in for a closer look at how the virus packages its genetic material as it assembles beneath the surface of an infected cell.

Related Articles


Their new work, published in the Proceedings of the National Academy of Sciences, visualizes for the first time the very beginning of particle formation, when the viral genome is trapped and then ensconced by a structural HIV protein named Gag. "We are beginning to see in better and better detail the steps involved, the order of things that occur in this process," says Sanford M. Simon, head of the Laboratory of Cellular Biophysics.

In collaboration with Paul Bieniasz, head of the Laboratory of Retrovirology and a scientist at the Aaron Diamond AIDS Research Institute, Simon is trying to figure out how HIV assembles inside an infected cell and then buds through the cell membrane on its way to infecting other cells. The hope is that the work will prove useful in developing treatments for the millions around the planet living with the lethal virus. The research also highlights a powerful imaging technique that Simon has been refining since 1992, which allows scientists to answer questions that in the past have been the subject of a guessing game.

The research, led by Nolwenn Jouvenet, a postdoc in the Bieniasz lab, employs total internal reflection fluorescence microscopy (TIR-FM), a technique very different from classical methods, which shine light through the whole cell. TIR-FM adjusts the angle of the light shined on the cell so that all of the light's energy is reflected at the cell's surface, illuminating only the events that occur within tens of nanometers of its outer membrane. This eliminates from view the background noise -- the bustling whirligig of activity farther within the cell -- and affords a relatively uncluttered view of what the researchers actually want to observe. "The key advance here is the ability to observe, in living cells, individual molecules of RNA that constitute the HIV genome," says Bieniasz, who is also a Howard Hughes Medical Institute investigator.

The team tagged the HIV protein Gag as well as HIV's genome with fluorescing molecules detectable by the microscope. They found that a very small number of Gag molecules, which are the crucial structural element of HIV particles, are required to tie down the otherwise footloose strand of HIV RNA. Newly formed RNA-Gag complexes move slowly on the membrane for several minutes recruiting more Gag to the complex, firmly anchoring it in place. Once the HIV genome is encapsulated by Gag, forming a new viral particle, it is ready to be released from the cell membrane to infect other cells.

The work dispels other models for HIV assembly that did not have the benefit of real-time, single-virion imaging. For example, it shows that new HIV particles are assembled at the cell membrane, not before they arrive there, and are constructed around individual genomes. While the new information may help scientists working on HIV drugs and vaccines, Jouvenet, Simon and Bieniasz also hope to use the microscopy technique to study what happens after the viral particle is formed -- how it buds through the membrane, and how it detaches from the host cell and becomes a free agent.


Story Source:

The above story is based on materials provided by Rockefeller University. Note: Materials may be edited for content and length.


Journal Reference:

  1. Jouvenet et al. Imaging the interaction of HIV-1 genomes and Gag during assembly of individual viral particles. Proceedings of the National Academy of Sciences, 2009; 106 (45): 19114 DOI: 10.1073/pnas.0907364106

Cite This Page:

Rockefeller University. "Imaging study shows HIV particles assembling around genome of infected cell." ScienceDaily. ScienceDaily, 2 January 2010. <www.sciencedaily.com/releases/2009/12/091231154404.htm>.
Rockefeller University. (2010, January 2). Imaging study shows HIV particles assembling around genome of infected cell. ScienceDaily. Retrieved October 24, 2014 from www.sciencedaily.com/releases/2009/12/091231154404.htm
Rockefeller University. "Imaging study shows HIV particles assembling around genome of infected cell." ScienceDaily. www.sciencedaily.com/releases/2009/12/091231154404.htm (accessed October 24, 2014).

Share This



More Health & Medicine News

Friday, October 24, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Breakfast Debate: To Eat Or Not To Eat?

Breakfast Debate: To Eat Or Not To Eat?

Newsy (Oct. 23, 2014) Conflicting studies published in the same week re-ignited the debate over whether we should be eating breakfast. Video provided by Newsy
Powered by NewsLook.com
Ebola Fears Keep Guinea Hospitals Empty

Ebola Fears Keep Guinea Hospitals Empty

AP (Oct. 23, 2014) Fears of Ebola are keeping doctors and patients alike away from hospitals in the West African nation of Guinea. (Oct. 23) Video provided by AP
Powered by NewsLook.com
Despite Rising Death Toll, Many Survive Ebola

Despite Rising Death Toll, Many Survive Ebola

AP (Oct. 23, 2014) The family of a Dallas nurse infected with Ebola in the US says doctors can no longer detect the virus in her. Despite the mounting death toll in West Africa, there are survivors there too. (Oct. 23) Video provided by AP
Powered by NewsLook.com
Orthodontist Mom Jennifer Salzer on the Best Time for Braces

Orthodontist Mom Jennifer Salzer on the Best Time for Braces

Working Mother (Oct. 22, 2014) Is your child ready? Video provided by Working Mother
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:

Strange & Offbeat Stories


Health & Medicine

Mind & Brain

Living & Well

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins