Figure 4

Particle stiffness regulates immature HIV-1 entry. Varying amounts of GFP-TM1 were incorporated into immature or mature HIV-1 bearing ΔCT Env (HXB2). The gp120 level represents all Env capable of mediating viral entry (ΔCT or WT Env). Error bars show SEM. Immature (orange dash) viruses bearing different amounts of GFP-TM1 were generated and analyzed together with immature WT (blue diamond) or mature WT (blue circle). (A) Virion stiffness (at least 19 particles were measured for each stiffness value) or (B) viral entry activity per Env normalized to the corresponding mature or immature ΔCT viruses.