In 1918, 50 million people died during a worldwide influenza pandemic caused by mutation of a bird-specific strain of the influenza virus. Recently H5N1, another highly infectious avian strain has caused outbreaks of bird flu around the world. There is great concern that this virus might also mutate to allow human-to-human transmission and cause another catastrophic pandemic.
Specific mutations in a viral protein, the polymerase, contribute to the ability of the bird virus to jump the species barrier to humans. Researchers from the European Molecular Biology Laboratory (EMBL) in Grenoble and Heidelberg, the Institut de Biologie Structurale (IBS) and the Unit of Virus Host Cell Interactions (UVHCI)*, both in Grenoble, have now produced the first 3-dimensional image of part of this key protein. The study, which is published in the current issue of Nature Structural and Molecular Biology, investigates the structure and function of the protein and sheds light on how polymerase mutations contribute to transmission of avian flu to humans.
Upon infection the influenza virus starts multiplying in the cells of an infected host. The polymerase is crucial in this process because it copies the viral genome and directs the production of its proteins. Interfering with polymerase function would prevent the virus replicating, thereby reducing the spread of the virus and the severity of the infection.
“For many years scientists have tried to understand the flu polymerase and to look for weak points that could be targeted by drugs,” says Darren Hart, whose team participated in the research at EMBL Grenoble. “But no one could get enough protein to analyse its structure. We developed a way to use robots to screen tens of thousands of experimental conditions and discovered a piece of the influenza polymerase that we could work with. It is a small part of the entire protein, but it provides interesting insights into how the protein works and how mutations may affect host range.”
Together with scientists at the IBS they visualized the atomic structure of the protein and discovered a previously overlooked signal that labels it for transport to the human nucleus where the genetic material of the virus is replicated. Cell microscopy studies at EMBL Heidelberg revealed that the human nuclear transport protein, importin alpha, recognises this signal and shuttles the polymerase into the nucleus. To find out how the polymerase and importin interact, Stephen Cusack, head of EMBL Grenoble, and collaborators at the UVHCI, used the high intensity X-ray source of the European Synchrotron Radiation Facility to generate a high-resolution image of the two proteins interacting with each other. The image revealed that mutations known to play a role in the transmission of avian influenza virus to mammals were located within, or close to, this site of interaction. This suggests that mutations may affect the efficiency of nuclear transport and through this the ability of the virus to replicate in different species.
“Interfering with polymerase function could provide new ways to treat or prevent flu,” says Cusack, “but this will require a detailed picture of the rest of the polymerase. This is what we are aiming for in our new FLUPOL project. In a joint effort with other European laboratories, and with financial support by the European Commission, we will explore both structure and function of this key drug target and try to characterise other mutations implicated in bird-to-human transmission.”
* The Unit of Virus Host Cell Interactions is a collaboration of the Centre National de la Recherche Scientifique (CNRS), the Université Joseph-Fourier in Grenoble and EMBL.
Anna-Lynn Wegener | alfa
First time-lapse footage of cell activity during limb regeneration
25.10.2016 | eLife
Phenotype at the push of a button
25.10.2016 | Institut für Pflanzenbiochemie
Ultrafast lasers have introduced new possibilities in engraving ultrafine structures, and scientists are now also investigating how to use them to etch microstructures into thin glass. There are possible applications in analytics (lab on a chip) and especially in electronics and the consumer sector, where great interest has been shown.
This new method was born of a surprising phenomenon: irradiating glass in a particular way with an ultrafast laser has the effect of making the glass up to a...
Terahertz excitation of selected crystal vibrations leads to an effective magnetic field that drives coherent spin motion
Controlling functional properties by light is one of the grand goals in modern condensed matter physics and materials science. A new study now demonstrates how...
Researchers from the Institute for Quantum Computing (IQC) at the University of Waterloo led the development of a new extensible wiring technique capable of controlling superconducting quantum bits, representing a significant step towards to the realization of a scalable quantum computer.
"The quantum socket is a wiring method that uses three-dimensional wires based on spring-loaded pins to address individual qubits," said Jeremy Béjanin, a PhD...
In a paper in Scientific Reports, a research team at Worcester Polytechnic Institute describes a novel light-activated phenomenon that could become the basis for applications as diverse as microscopic robotic grippers and more efficient solar cells.
A research team at Worcester Polytechnic Institute (WPI) has developed a revolutionary, light-activated semiconductor nanocomposite material that can be used...
By forcefully embedding two silicon atoms in a diamond matrix, Sandia researchers have demonstrated for the first time on a single chip all the components needed to create a quantum bridge to link quantum computers together.
"People have already built small quantum computers," says Sandia researcher Ryan Camacho. "Maybe the first useful one won't be a single giant quantum computer...
14.10.2016 | Event News
14.10.2016 | Event News
12.10.2016 | Event News
26.10.2016 | Awards Funding
26.10.2016 | Power and Electrical Engineering
26.10.2016 | Health and Medicine