FIG. 8.

hStau overexpression results in enhanced genomic RNA content in virions and dramatically reduces infectivity. 293T cells were transfected with 10 μg of pNL4.3 (plus vector control) or pNL4.3 with hStau-HA cDNA expressor, pNL4.3/hStau-HA (hStau-1, 1 μg; hStau-2, 5 μg). (A) At 48 h posttransfection, virus was harvested and hStau and p17 were identified by Western analysis. Genomic RNA levels were determined by Northern blot analysis, and the results from three experiments (± standard deviation) are presented in panel B. RNA levels in pNL4.3 were arbitrarily set to 1. Only one concentration of hStau-HA was tested (hStau-1). (C) A sensitive RT-PCR method was used to quantitate the number of copies of HIV-1 genomic RNA per virion from hStau-overexpressing cells as described in Materials and Methods. The average (± standard deviation) from two independent determinations is shown. (D) Results from infectivity assays in hStau overexpression studies. BF-24 monocytic indicator cells were infected with virus from mock-, pNL4.3- or pNL4.3-hStau-HA-transfected cells. A representative result from a CAT assay is shown; the bottom panel shows the average virus infectivity levels (±SEM) from three separate experiments. These effects were dose dependent.