Figure 4
From: Identification of critical residues of influenza neuraminidase in viral particle release
Characterization of critical residues necessary for NA function. A, relative infectivites of pseudovirions produced in the presence of NAH N234Y, I257M and K286E single and combined substitution mutants (N2 numbering). Experiments were performed in triplicates and repeated several times, and error bars indicate standard deviations. B, hemagglutination activity of NAH substitution panel. C, neuraminidase activity of NAH substitutions measured by the release of fluorogenic substrate 4-MUNANA. Enzyme activity is presented as the fold-change of triplicate samples. Experiments were performed in triplicates and repeated several times, and error bars indicate standard deviations. D, western blot of HA and NA expression in 293T cell lysates and incorporation onto HIV particles. The HA precursor (HA0), and proteolytic subunits (HA1 and HA2) are detected in both cell and virus lysates.