Global Rescue of Defects in HIV-1 Envelope Glycoprotein Incorporation: Implications for Matrix Structure
Figure 2
Identification of a second-site mutant capable of rescuing diverse Env-incorporation defective mutants.
(A) Jurkat cells were transfected with the indicated molecular clones. At 2-day intervals the cells were split and samples of media were assayed for RT activity. Virus from the WT and 16EK peaks was normalized by RT then used to infect naïve Jurkat cells and replication of the second passage was followed as described above. Genomic DNA was extracted from cells at the time of peak replication in the 16EK samples after both first and second passage cultures, and the MA coding region was amplified by PCR and subjected to DNA sequencing, revealing the original (16EK) and second-site compensatory (62QR) mutations. (B) Jurkat cells were transfected with the indicated molecular clones and replication was monitored as in (A). (C+E) 293T cells were transfected with the indicated molecular clones. At 24 h, supernatants were filtered then virions were pelleted, lysed, and probed by western blotting for gp41 and CA. (D+F) Supernatants were harvested and assayed for infectivity as described in Materials and Methods. Env incorporation was determined as described in Materials and Methods. Infectivity and Env incorporation are expressed relative to the WT value. n = 3, +/− SEM.