Figure 4: Preparation of the full-length rH7 HA0. (a) Baculovirus expression cassette for rH7 derived from A/Anhui/1/2013 (H7N9) influenza virus. Indicated within rH7 HA0 are locations of the baculovirus polyhedrin promoter (PolH), HA0 signal peptide (SP), trans-membrane domain (TM), and C-terminus (CT). (b) Transmission electron microscopy of purified rH7. The rH7 preparation was negatively stained with 1% phosphotungstic acid and visualized on a Hitachi H-7600 transmission electron microscope. Bar, 100nm.