Extended Data Fig. 4: Further examples of hybrid particles.

(a and b) show two z-positions through the same hybrid particle, which also displays pseudotyping in RSV-like region. (a) IAV-like regions extend from the top of the filament and ring-shaped densities corresponding to RSV genome, indicated by green arrows and highlighted in magnified inset image, are present within the virion. (b) The surface of the virion is covered in glycoproteins that are consistent in shape and arrangement with IAV glycoproteins, highlighted in magnified inset. Scale bars indicate 200 nm. (c) Tomogram shows a further example of a hybrid particle with two IAV-like regions which are joined to the RSV-like region by a continuous membrane. Black and green arrows indicate IAV and RSV RNP respectively, contained with in their associated structural regions. Scale bar indicates 200 nm. There is a clear shared lumen which continues between RSV and IAV regions, highlighted within magnified inset which corresponds to region marked by white dashed box. Scale bar indicates 50 nm. Micrographs shown in (a-c) representative of n = 3 biologically independent experiments.