Cryomicroscopy of lipid-enveloped virus entry and assembly

About the project

About the Project A 2027 Crick PhD project with Peter Rosenthal. Project background and description Our group studies the architecture of large protein and membrane assemblies to understand basic molecular mechanisms involved in virus infection. We apply cryo-EM to understand the structure and function of lipid-enveloped viruses such as influenza virus and retroviruses. We are interested in understanding how viruses enter cells by binding to cell surface receptors, how virus membranes fuse with host membranes, and also how viruses assemble and release from the cells. We have previously performed high-resolution studies of influenza A and C virus ultrastructure by electron cryotomography (cryo-ET) that have revealed the internal architecture of the viruses as well as the structure of envelope glycoproteins in situ. Influenza virus A membrane fusion is mediated by conformational changes in the hemagglutinin (HA) that occur at the low pH of the endosome. We have also visualised influenza virus directly fusing with membranes by cryo-ET and structural transformations in the HA by single particle cryo-EM. The main goal of this project is to directly image essential steps in lipid-enveloped virus infection of cells by cryo-EM and cryo-ET in combination with imaging studies of viruses, viral proteins and model membranes in vitro. For influenza viruses, this will help us understand how glycoprotein structural changes at low pH mediate transformations in membranes and also how viruses assemble by budding at the cell membrane. We are also interested in related studies of retroviruses and recently have shown that the envelope glycoprotein of spumaretroviruses, a family of retroviruses, is structurally similar to the membrane fusion proteins of paramyxoviruses and pneumoviruses. We are therefore interested in understanding how these glycoproteins mediate entry into cells as well as how their interactions drive the assembly of virus particles. We anticipate that results from both these systems will be important to understanding a wide range of assembly and membrane fusion processes in biology. The student will receive training in experimental cryomicroscopy (single particle cryo-EM, cryo-ET, FIB-milling, subtomogram averaging), computational image analysis, protein, membrane and virus methods, biophysical methods, and imaging of cells by light microscopy. We also work on structural problems associated with other protein molecular machines, organelles and cellular architecture. In addition, we explore methods for improving experimental imaging and improving computational methods for image analysis related to the above projects. While a single studentship is available, other topics for study will be considered in consultation with the advisor. Candidate background This multidisciplinary project will interest students with a background in structural biology, virology or cell biology. The ideal candidates will have experience of experimental methods in molecular biology, virology, and a strong background or interest in the physical sciences or computation. Students with an interest in methodological aspects of electron imaging or computation are also encouraged to apply. Lab-specific question Identify a finding, technique or approach from your previous research that you think could be relevant to our work. How might you apply or develop this in a PhD project in our lab?

Research areas