Figure 5: Preparation of influenza VLPs containing the full-length rH7 HA0, as well as NA and M1 proteins. (a) Baculovirus expression cassette and schematic composition of VLP comprised of rH7 protein derived from A/Shanghai/2/2013 (H7N9) virus, as well as NA and M1 proteins derived from A/Puerto Rico/8/1934 (H1N1) virus. Indicated within the baculovirus expression cassette are rH7 HA0 (open box), NA and M1 (solid boxes), as well as baculovirus polyhedrin promoters (arrows). (b) Transmission electron microscopy of purified rH7 VLPs. The VLP preparation was negatively stained with 1% phosphotungstic acid and visualized on a Hitachi H-7600 transmission electron microscope. Bar, 100nm.