Activity and localization of N-terminal deletion mutants. Schematic (A), western blotting (B), antiviral activity (C), and immunofluorescence microscopy (D) of N-terminal deletion mutants. Panel C results represent the geometric mean of at least 6 independent experiments, with error bars denoting 95% confidence intervals. All mutant proteins restricted HIV-1 infection to significantly lower levels than WT MxB (P <0.002). The bars in panel D represent 10 μm.