Dynamics of HIV-1 Assembly and Release
Figure 2
The three phases of HIV-1 assembly.
(A–B) Intensity traces of two individual Gag.eGFP clusters indicated with an arrow (A) and arrow head (B) in Figure 1 recorded in TIRF (black line) and WF (grey line) modes are shown in the top panels. Three phases, separated here by dashed lines, can be observed: Phase I) a rapid rise in fluorescence intensity, Phase II) a plateau region with fluctuations in fluorescence intensity, and Phase III) a decay of the fluorescence signal. The middle panels show the intensity traces of the local background. The bottom panel displays a plot of the corresponding instantaneous velocities of the particles. In A, an abrupt increase in instantaneous velocity is observed concomitantly with the onset of Phase III. (C) Trajectory of the individual Gag.eGFP cluster from panel A color-coded according to the three different phases. The scale bar represents 1 µm. (D) A mean-square displacement analysis of the trajectory shown in panel C indicates the random character of motion in the different phases and shows a change by two orders of magnitude in diffusion coefficient between the phases I+II and III.