Figure 9. CBP80 and eIF4E co-sediment with the polyribosomes.

(A) HEK293 cells were transfected with HIV-1^{HxBruR−/RI−} for 48 hour, cytoplasmic extracts were harvested, incubated in buffer with or without EDTA, and separated on 15–47.5% linear sucrose density gradients. Representative A₂₅₄ ribosomal RNA profiles are indicated. (B) Lysates from every other fraction were immunoblotted with CBP80 and eIF4E antibodies. (C) RNA was isolated and subjected to RNase protection assays with ³²P-labeled antisense RNA probe complementary to the HIV-1 5′ UTR and gag or actin, respectively. Detection products are the unspliced HIV-1 RNA (US), spliced HIV-1 transcripts (S) and cellular actin RNA.