Fig. S4.

Effect of NA glycosylation. (A) The TLC showed that all WSN NA mutated variants as shown could not cleave 3-SL. (B) Measurements of the NA activity of viruses as indicated at various temperatures by 4-MUNANA assay. Mean ± SEM for five independent experiments. *P < 0.001. (C) Western blot analysis of 44-72-G and 44-72-219-G viruses after treatment with the endoglycosidase mixture (F1, F2, F3, and H). The filter was probed with anti-NA antibody. Viral morphology as examined by transmission electron microscopy for (D) 44-G virus, (E) 72-G virus, and (F) 44-72-G virus.