Figure 7. A model for selective HIV-1 genome packaging.
Cytosolic Gag (light gray triangles) is inhibited from membrane association by its association with tRNA (yellow). Gag (triangles and hexagons, colored dark gray where forming specific contacts with the packaging signal) binding viral genomic RNA (red; thick portions correspond to the 5’UTR, thin portions to the remainder, not shown to scale) has a higher probability to overcome this inhibition and associate with the plasma membrane. The selectivity of membrane-bound Gag for the viral genome necessitates CA-CA immature lattice contacts.