XML Feed for RxPG News   Add RxPG News Headlines to My Yahoo!   Javascript Syndication for RxPG News

Research Health World General
 
  Home
 
 Latest Research
 Cancer
 Psychiatry
 Genetics
 Surgery
 Aging
 Ophthalmology
 Gynaecology
 Neurosciences
 Pharmacology
 Cardiology
 Obstetrics
 Infectious Diseases
 Respiratory Medicine
 Pathology
 Endocrinology
 Immunology
 Nephrology
 Gastroenterology
 Biotechnology
 Radiology
 Dermatology
 Microbiology
  Virology
   West Nile Virus
  Bacteriology
 Haematology
 Dental
 ENT
 Environment
 Embryology
 Orthopedics
 Metabolism
 Anaethesia
 Paediatrics
 Public Health
 Urology
 Musculoskeletal
 Clinical Trials
 Physiology
 Biochemistry
 Cytology
 Traumatology
 Rheumatology
 
 Medical News
 Health
 Opinion
 Healthcare
 Professionals
 Launch
 Awards & Prizes
 
 Careers
 Medical
 Nursing
 Dental
 
 Special Topics
 Euthanasia
 Ethics
 Evolution
 Odd Medical News
 Feature
 
 World News
 Tsunami
 Epidemics
 Climate
 Business
Search

Last Updated: Aug 19th, 2006 - 22:18:38

Virology Channel
subscribe to Virology newsletter

Latest Research : Microbiology : Virology

   DISCUSS   |   EMAIL   |   PRINT
Cracking Virus Protection Shield
Jun 19, 2006, 02:18, Reviewed by: Dr. Priya Saxena

Scientists reveal the structure of a protein that packages the viral genome and helps viruses to replicate while avoiding human immune reactions.

 
Ebola, measles and rabies are serious threats to public health in developing countries. Despite different symptoms all of the diseases are caused by the same class of viruses that unlike most other living beings carry their genetic information on a single RNA molecule instead of a double strand of DNA. Now researchers from the Institut de Virologie Moléculaire et Structurale [IVMS] and the Outstation of the European Molecular Biology Laboratory [EMBL] in Grenoble have obtained a detailed structural picture of a protein that allows the rabies virus to withstand the human immune response and survive and replicate in our cells. The study that is published in this week's online edition of Science suggests new potential drug targets in rabies and sheds light on how similar approaches can help fighting other viral diseases.

When the rabies virus enters a human cell through the membrane, the RNA molecule that carries its genes is transported into the centre of the cell. Here it redirects the cellular machinery of the host to produce many new copies of the virus that go on to infect more cells. One molecule that is crucial in this process is a viral protein called nucleoprotein. The protein ensures that on its way through the cell the virus RNA is not destroyed by the immune response of the host.

"Nucleoprotein is vital for the rabies virus," says Rob Ruigrok, Head of the IVMS. "It is one of the few proteins that the virus brings into the host cell and it wraps around the RNA like a protection shield. Without this shield the RNA would be degraded by the enzymes of the human immune system that try to eliminate the invader."

To investigate how exactly this protection shield works, Aurélie Albertini from Ruigrok's team obtained crystals of nucleoprotein bound to RNA. Examining the crystals with high-intensity X-ray sources at the European Synchrotron Radiation Facility [ESRF], Amy Wernimont from Winfried Weissenhorn's group at EMBL Grenoble produced a high-resolution image of the protein.

"Nucleoprotein acts like a clamp," says Weissenhorn. "It consists of two domains that like two jaws clasp around the RNA strand. Many nucleoproteins bind side-by-side along the length of an RNA molecule and make it inaccessible for degrading enzymes but also for the machinery needed to replicate the virus. This means that the protection shield must be flexible and able to distinguish between different types of enzymes trying to gain access."

The detailed structural picture suggests that upon a signal a part of the protein located between the two main domains might act as a hinge that moves the upper jaw out of the way when time for replication has come.

"This dynamic mechanism makes nucleoproteins an excellent drug target," says Ruigrok, "Small agents that bind to the protein in such a way to block its flexibility and keep it in the closed state, would prevent replication of the virus and would stop it from spreading."

Rabies virus shares this protection strategy with other viruses of its class; in Ebola, measles and Borna virus similar complexes of RNA and nucleoproteins have been found.

"This means that our results do not only have implications for the design of new drugs against rabies, but they suggest new therapeutic approaches in a variety of diseases, some of which are much more threatening than rabies. On a different note, the conservation of the nucleoprotein system also leaves room for evolutionary speculations about common ancestors and primordial infectious units of RNA viruses," Weissenhorn concludes.
 

- A.A.V. Albertini, A.K. Wernimont, T. Muziol, R.G.B. Ravelli, C.R. Clapier, G. Schoehn, W. Weissenhorn & R. Ruigrok. Crystal structure of the rabies virus nucleoprotein-RNA complex, Science online, 15 June 2006
 

www.embl.org

 
Subscribe to Virology Newsletter
E-mail Address:

 

The European Molecular Biology Laboratory is a non-profit organisation and a basic research institute funded by public research monies from 19 member states. Research at EMBL is conducted by approximately 80 independent groups covering the spectrum of molecular biology. The Laboratory has five units: the main Laboratory in Heidelberg, and Outstations in Hinxton [the European Bioinformatics Institute], Grenoble, Hamburg, and Monterotondo near Rome.

The cornerstones of EMBL's mission are: to perform basic research in molecular biology, to train scientists, students and visitors at all levels, to offer vital services to scientists in the member states, to develop new instruments and methods in the life sciences, and technology transfer.

EMBL's international PhD Programme has a student body of about 170. The Laboratory also sponsors an active Science and Society programme.


Related Virology News

How West Nile virus evades immune defenses
Innovative method for creating a human cytomegalovirus vaccine outlined
Cracking Virus Protection Shield
Viruses trade-off between survival and reproduction
New hybrid virus provides targeted molecular imaging of cancer
Mass spectrometry to detect norovirus particles
xCT molecule is a major gateway for KSHV to enter human cells
Surprising discovery about the inner workings of vesicular stomatitis virus (VSV)
New human retrovirus - Xenotropic MuLV-related virus (XMRV)
Viruses can be forced to evolve as better delivery vehicles for gene therapy


For any corrections of factual information, to contact the editors or to send any medical news or health news press releases, use feedback form

Top of Page

 

© Copyright 2004 onwards by RxPG Medical Solutions Private Limited
Contact Us