Fig. 2. Effects of Capsid Stability on ERT Efficiency.

(A) Stability of HIV-1 capsids composed of wild type (WT) or the indicated CA mutant subunits. Capsid stability was assessed by treating virions with melittin to release cores into lysate-free ERT buffers that contained different IP₆ levels, and then quantifying the numbers of apparently intact capsids (insets; scale bars, 100 nm) by imaging with negative stain transmission electron microscopy (TEM). Graphs report the mean and standard deviation (n=3) of intact cores per 900 μm² under the different conditions (see Materials and Methods and Fig. S1 for details). (B) ERT levels from cores with WT or mutant CA proteins at different IP₆ concentrations. Grey bars highlight IP₆ concentrations that optimized transcript numbers. Standard “non-lysate” conditions were used for these experiments, except for variations in IP₆ levels.