FIGURE 3.

Mutations destroying the ²⁶⁰NGS²⁶² glycosylation site result in decreased gp120 levels in the virion. A, Western blot of virion-associated Env expression of wild-type or mutant gp120 virions, produced in 293T cells. Viral pellets were obtained after high speed centrifugation, and 50 ng of p24 was loaded per lane. The N260Q mutant virus shows markedly lower expression of both gp120 and gp41. Also, when the Ser at position 262 is mutated into an Ala or a Cys, the mutant virus contains hardly detectable gp120 levels in the envelope. B, band intensities of the Western blot in A were quantified using the program ImageJ.