Visualizing virus replication in three dimensions

May 07, 2009
This is the cover illustration of the newest issue of Cell Host & Microbes. In the background in gray is a normal, two-dimensional image of the virus on an electron microscope. The 3D model is superimposed. The tubules of the endoplasmic reticulum and inside them the balloon-like vesicles where the dengue virus replicates its genome can be seen. Credit: Hygiene Institute at Heidelberg University Hospital

Dengue fever is the most common infectious disease transmitted by mosquitoes - some 100 million people around the world are infected. Researchers at the Hygiene Institute at Heidelberg University Hospital were the first to present a three-dimensional model of the location in the human cell where the virus is reproduced.

Their research provides an insight into the exact process of and serves as a model for other viruses whose replication is still unclear, such as the . In addition, it offers new approaches for developing measures to prevent or treat dengue fever. Up to now, neither a vaccine nor a specific antiviral therapy exists.

Professor Dr. Ralf Bartenschlager, director of the Department of at the Heidelberg Hygiene Institute and his team, working in cooperation with colleagues from the European Molecular Biology Laboratory (EMBL) have published their study in the latest issue of the prestigious journal Cell Host & Microbes.

Viruses do not have a metabolism and cannot produce proteins from their genetic material (RNA or DNA) on their own. They can replicate only inside a host cell - but where and how exactly does this take place? The answer to this question is crucial for developing therapy.

Viruses transform human cell membranes for their purposes

Dengue viruses reproduce in what is known as the endoplasmic reticulum, a membrane network interconnected with the nuclear envelope; this is where proteins are synthesized. The dengue virus uses this membrane network and transforms it for its own use.

"We now know that viral RNA is replicated in vesicles in the endoplasmic reticulum and is secreted through tiny pores. We were also able to show that replication of the virus genome and its encapsulation in new virus particles are directly linked," said Professor Bartenschlager. The new virus genomes are secreted through pores into the intracellular space where they are incorporated into pre-stages of viruses and then penetrate the endoplasmic reticulum a second time. There they are enveloped in a membrane that disguises them for the cell so that they can be secreted like normal cellular material. The reproduction cycle can begin again.

More information: Sonja Welsch, Sven Miller, Ines Romero-Brey, Andreas Merz, Christopher Bleck, Paul Walther, Stephen D. Fuller, Claude Antony, Jacomine Krijnse-Locker, Ralf Bartenschlager, Composition and Three-Dimensional Architecture of the Dengue Replication and Assembly Sites, Cell Host & Microbes 2009, 5, 4.

Source: University Hospital Heidelberg (news : web)

Explore further: Researchers discover new strategy germs use to invade cells

add to favorites email to friend print save as pdf

Related Stories

Penn researchers discover new mechanism for viral replication

Aug 16, 2007

Researchers at the University of Pennsylvania School of Medicine have identified a new strategy that Kaposi’s Sarcoma Associated Herpesvirus (KSHV) uses to dupe infected cells into replicating its viral genome. This allows ...

Recommended for you

Researchers discover new strategy germs use to invade cells

Aug 20, 2014

The hospital germ Pseudomonas aeruginosa wraps itself into the membrane of human cells: A team led by Dr. Thorsten Eierhoff and Junior Professor Dr. Winfried Römer from the Institute of Biology II, members of the Cluster ...

Progress in the fight against harmful fungi

Aug 20, 2014

A group of researchers at the Max F. Perutz Laboratories has created one of the three world's largest gene libraries for the Candida glabrata yeast, which is harmful to humans. Molecular analysis of the Candida ...

How steroid hormones enable plants to grow

Aug 19, 2014

Plants can adapt extremely quickly to changes in their environment. Hormones, chemical messengers that are activated in direct response to light and temperature stimuli help them achieve this. Plant steroid ...

Surviving the attack of killer microbes

Aug 19, 2014

The ability to find food and avoid predation dictates whether most organisms live to spread their genes to the next generation or die trying. But for some species of microbe, a unique virus changes the rules ...

Histones and the mystery of cell proliferation

Aug 19, 2014

Before cells divide, they create so much genetic material that it must be wound onto spools before the two new cells can split apart. These spools are actually proteins called histones, and they must multiply ...

User comments : 0