FIG 5.

A tyrosine motif in the NiV F cytoplasmic tail modulates NiV F budding. (A) Schematic for the cytoplasmic tail of NiV F designating the region being alanine screened. (B) HEK293T cells were transfected for 24 h with an empty vector, wild-type NiV F, or one of the four alanine mutants of region T2. Both cell lysates and VLPs were harvested and run in SDS-PAGE followed by Western blot analysis. (C) Densitometry was used to quantify band intensity for cell lysates and VLPs. In addition, flow cytometric analyses were used to evaluate the levels of CSE for each of the mutants relative to the WT. (D) The cell lysate and VLP band intensities were used to calculate budding indices and all were normalized to wild-type F. A similar index is also shown using values for VLP intensity and corresponding CSE values. Mutants exhibiting budding at levels significantly below WT have their values in black. Error bars designate values for standards error of the mean. Three or more independent experiments were used for each ratio, and the statistical significance was evaluated with one-sample t tests.