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 Speed data for the brain’s navigation system
06.12.2016 | Deutsches Zentrum für Neurodegenerative Erkrankungen e.V. (DZNE)

nachricht Study suggests possible new target for treating and preventing Alzheimer's
02.12.2016 | Oregon Health & Science University

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: Shape matters when light meets atom

Mapping the interaction of a single atom with a single photon may inform design of quantum devices

Have you ever wondered how you see the world? Vision is about photons of light, which are packets of energy, interacting with the atoms or molecules in what...

Im Focus: Novel silicon etching technique crafts 3-D gradient refractive index micro-optics

A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.

Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...

Im Focus: Quantum Particles Form Droplets

In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.

“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...

Im Focus: MADMAX: Max Planck Institute for Physics takes up axion research

The Max Planck Institute for Physics (MPP) is opening up a new research field. A workshop from November 21 - 22, 2016 will mark the start of activities for an innovative axion experiment. Axions are still only purely hypothetical particles. Their detection could solve two fundamental problems in particle physics: What dark matter consists of and why it has not yet been possible to directly observe a CP violation for the strong interaction.

The “MADMAX” project is the MPP’s commitment to axion research. Axions are so far only a theoretical prediction and are difficult to detect: on the one hand,...

Im Focus: Molecules change shape when wet

Broadband rotational spectroscopy unravels structural reshaping of isolated molecules in the gas phase to accommodate water

In two recent publications in the Journal of Chemical Physics and in the Journal of Physical Chemistry Letters, researchers around Melanie Schnell from the Max...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ICTM Conference 2017: Production technology for turbomachine manufacturing of the future

16.11.2016 | Event News

Innovation Day Laser Technology – Laser Additive Manufacturing

01.11.2016 | Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

 
Latest News

Speed data for the brain’s navigation system

06.12.2016 | Health and Medicine

What happens in the cell nucleus after fertilization

06.12.2016 | Life Sciences

IHP presents the fastest silicon-based transistor in the world

05.12.2016 | Power and Electrical Engineering

VideoLinks
B2B-VideoLinks
More VideoLinks >>>