Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

UIC scientists provide first images of HIV in living cells

12.12.2002


In stunning color images using time-lapse microscopy, researchers at the University of Illinois at Chicago have for the first time captured the very earliest stages of HIV infection in living cells.



The researchers filmed individual HIV particles as they traveled to the nucleus of a human cell and began taking over its genetic machinery -- the first step in the destruction of the body’s immune system that leads to AIDS.

The movies not only offer tantalizing glimpses of HIV in action, but provide visual proof that HIV enlists the assistance of its host to wreak havoc on the body’s defenses.


The virus can be seen traveling along a part of the host cell’s own skeletal framework of microtubules as it makes its way from the outer membrane to the nucleus. The virus hitches a ride aboard a multi-unit protein called dynein, commonly referred to as a molecular motor.

"Dynein is like a tractor trailer, the microtubules are the highway, and the HIV particles are the cargo," said David McDonald, assistant professor of microbiology and immunology at UIC.

McDonald and Thomas Hope, associate professor of microbiology and immunology at UIC, are co-authors of the study, which appeared Nov. 11 in the Journal of Cell Biology. Science magazine named the paper an "editor’s choice" in its Nov. 22 issue, and it will be featured in an upcoming issue of Nature Cell Biology.

An editorial accompanying the paper said, "With the powerful approaches developed by McDonald et al. and the incredible progress in imaging single fluorescent molecules in living cells, ... important and fascinating questions of HIV cell biology can now be addressed."

Until recently, little was known about how HIV enters a cell. The virus is made of an outer shell, or envelope, and a core, referred to as a particle, which is composed of proteins and genetic material. When the virus attacks an immune cell, it fuses with the cell’s membrane and releases its particle core inside.

But what those particles do once they are inside -- in particular, how they arrive at the nucleus to hijack the cell’s genetic machinery and begin reproducing their own DNA -- had remained a mystery.

The tiny particles, only about 12 millionths of a centimeter in diameter, have to cross a distance that is up to 500 times their size to reach the nucleus. Moreover, the way is blocked by all kinds of cellular structures, from energy-generating mitochondria to packets of proteins. How do the particles get through this obstacle course?

The researchers were able to visualize individual HIV particles by attaching green fluorescent protein to one of their components. Derived from jellyfish, the protein has only recently been discovered as a means of tagging individual molecules inside a living cell. When blue light shines on the protein, it gives off a green glow.

The researchers also made the microtubules of the host cells glow a deep red by incorporating another fluorescent protein into their building blocks.

Pictures of living cells infected with HIV were taken under a microscope at intervals as short as 15 seconds, creating a movie of the viruses’ activities as they traversed the microtubular highway toward their destination in the nucleus.

"They don’t make a beeline for the nucleus," McDonald said. "Their progress is somewhat halting. They appear to jump from one microtubule to another, moving in a jagged path, even sometimes moving backward. But they eventually reach their destination."

The journey to the nucleus takes about two to four hours, he said.

At the periphery of the nuclei, the scientists saw the viruses form complexes with genetic material of the host cells -- appropriating the tools that HIV needs to reproduce.

Dynein’s role was confirmed by injecting an off-the-shelf antibody into the cells that prevents the molecular motors from working. When the motors stop, the viral particles are found scattered throughout the host cells, not congregated around the cells’ nuclei.

The paper represents four years of research, begun when Hope was a researcher at the Salk Institute for Biological Sciences in La Jolla, Calif.

"This work is confirmation of the dynamic new methods we are using to study HIV," Hope said. "We hope this basic research will one day lead to new targets for drug therapy in the longstanding battle against AIDS."

Hope said he plans to extend the technique developed in this HIV research to study Ebola, one of the deadliest viruses known and one that could be used in a bioterrorist attack. Little is understood about Ebola’s basic biology, including how it enters cells.

Sharon Butler | EurekAlert!
Further information:
http://www.uic.edu

More articles from Health and Medicine:

nachricht New malaria analysis method reveals disease severity in minutes
14.08.2017 | University of British Columbia

nachricht New type of blood cells work as indicators of autoimmunity
14.08.2017 | Instituto de Medicina Molecular

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: Fizzy soda water could be key to clean manufacture of flat wonder material: Graphene

Whether you call it effervescent, fizzy, or sparkling, carbonated water is making a comeback as a beverage. Aside from quenching thirst, researchers at the University of Illinois at Urbana-Champaign have discovered a new use for these "bubbly" concoctions that will have major impact on the manufacturer of the world's thinnest, flattest, and one most useful materials -- graphene.

As graphene's popularity grows as an advanced "wonder" material, the speed and quality at which it can be manufactured will be paramount. With that in mind,...

Im Focus: Exotic quantum states made from light: Physicists create optical “wells” for a super-photon

Physicists at the University of Bonn have managed to create optical hollows and more complex patterns into which the light of a Bose-Einstein condensate flows. The creation of such highly low-loss structures for light is a prerequisite for complex light circuits, such as for quantum information processing for a new generation of computers. The researchers are now presenting their results in the journal Nature Photonics.

Light particles (photons) occur as tiny, indivisible portions. Many thousands of these light portions can be merged to form a single super-photon if they are...

Im Focus: Circular RNA linked to brain function

For the first time, scientists have shown that circular RNA is linked to brain function. When a RNA molecule called Cdr1as was deleted from the genome of mice, the animals had problems filtering out unnecessary information – like patients suffering from neuropsychiatric disorders.

While hundreds of circular RNAs (circRNAs) are abundant in mammalian brains, one big question has remained unanswered: What are they actually good for? In the...

Im Focus: RAVAN CubeSat measures Earth's outgoing energy

An experimental small satellite has successfully collected and delivered data on a key measurement for predicting changes in Earth's climate.

The Radiometer Assessment using Vertically Aligned Nanotubes (RAVAN) CubeSat was launched into low-Earth orbit on Nov. 11, 2016, in order to test new...

Im Focus: Scientists shine new light on the “other high temperature superconductor”

A study led by scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg presents evidence of the coexistence of superconductivity and “charge-density-waves” in compounds of the poorly-studied family of bismuthates. This observation opens up new perspectives for a deeper understanding of the phenomenon of high-temperature superconductivity, a topic which is at the core of condensed matter research since more than 30 years. The paper by Nicoletti et al has been published in the PNAS.

Since the beginning of the 20th century, superconductivity had been observed in some metals at temperatures only a few degrees above the absolute zero (minus...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Call for Papers – ICNFT 2018, 5th International Conference on New Forming Technology

16.08.2017 | Event News

Sustainability is the business model of tomorrow

04.08.2017 | Event News

Clash of Realities 2017: Registration now open. International Conference at TH Köln

26.07.2017 | Event News

 
Latest News

A Map of the Cell’s Power Station

18.08.2017 | Life Sciences

Engineering team images tiny quasicrystals as they form

18.08.2017 | Physics and Astronomy

Researchers printed graphene-like materials with inkjet

18.08.2017 | Materials Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>