Nanoscale exploration of the multiplication of the human Respiratory Syncytial Virus
Lorène Gonnin, Catarina S. Silva, Brandon Le Bon, Ambroise Desfosses, Madalen Le Gorrec, Maria Bacia, Irina Gutsche
Our group has a long-term interest in nonsegmented negative strand RNA viruses. After several years of studies of Paramyxoviridae (Measles) and Rhabdoviridae (Vesicular Stomatitis and Rabies), we shifted to Pneumoviridae and their most well-known representative, Respiratory Syncytial virus. RSV is the leading cause of infantile bronchiolitis and pneumonia worldwide, with the burden on elderly comparable to influenza. Whereas the freshly introduced vaccines target only the pregnant women and the elderly, the majority of population, including infants and children, lack vaccination and therapeutic options. To establish and spread infection, the virus amplifies its genome within infected cells and transmits it to neighbouring cells. The genomic RNA, enwrapped into a helical nucleocapsid, is transcribed and replicated by the viral polymerase. The resulting ribonucleoprotein particle (RNP) performs viral RNA synthesis inside the cytoplasmic viral factories, formed by liquid-liquid phase separation. Once enough RNPs are produced, they are transported to the plasma membrane for packaging into new virions. We have recently dissected the structural landscape of the helical RSV nucleocapsids in vitro by cryo-EM. The structures of the other viral proteins involved are also mostly solved, and the virion shell has recently been structurally characterised. However, how the different viral players cooperate, how they coopt their cellular partners, and how the viral cycle is regulated is yet largely unexplored. To achieve a spatio-temporal and mechanistic understanding of these processes, we joined a consortium investigating the RSV multiplication using a rich palette of complementary strategies. In our group, we apply a variety of electron microscopy techniques such as single particle cryo-EM, cellular EM, CLEM, cryo-FIB/SEM, in situ cryo-ET and cryo-CLEM. In parallel, we adapt and develop associated image analysis tools and workflows.
Collaborations :
– Marie Galloux, Julien Sourimant, Monika Bajorek and Jean-François Eléouët, INRAE, Jouy-en-Josas
– Marie-Anne Rameix-Welti, Pasteur Institute, Paris
– Lorène Gonnin, Linda Sandblad and UCEM, Umeå University, Sweden
– Max Renner, Umeå University, Sweden
– Takayuki Uchihashi, Nagoya University, Japan
– Tuomas Knowles, University of Cambridge, UK
– Cédric Leyrat, IGF, Montpellier