Figure 4. Nuclear export of intron-containing HTLV-1 mRNAs is blocked in latently infected cells, but can be rescued by Rex.
(A) Nuclear to cytoplasmic ratios of Gag-Pol and pXIII mRNAs. The ratios were determined as in Materials and Methods by normalizing the level of the nuclear or cytoplasmic mRNA of interest to the respective nuclear or cytoplasmic β-actin mRNA in each mRNA preparation. (B) Reactivation of Gag expression in latently infected cell lines (LIC 1, 2, and 3) by Rex. Each of the three latently infected cell lines (3×105 cells per well in a 6-well plate) were transfected with either a Tax (Bc12-Tax) or a Rex (pRSV-Rex) expression construct using Fugene reagent (Promega) for 48 hours. Whole cell lysates were analyzed by immunoblotting using antibodies against p24, p19, Tax, Rex, and β-actin (Actin).