Figure 4. Correlation between the nuclear localization of NiV-M and VLP budding.

Viral-like particles were harvested from culture supernatants of cells expressing wild-type NiV-M, NLS mutants (A) or NES mutants (B) at 24 hpt as described in Materials and Methods . VLPs and the corresponding cell lysates were immunoblotted with an anti-FLAG antibody. The cell lysate blots were then stripped and re-probed with an anti-β-tubulin antibody as loading control. Representative results are shown in (A) and (B). (C) and (D) show the quantification of the budding index for the indicated wild-type and mutant NiV-M proteins as described in Materials and Methods . Error bars were calculated from three independent experiments. M mutants that were deficient in either nuclear import or export were also deficient in budding.