Impact of Viral Activators and Epigenetic Regulators on HIV-1 LTRs Containing Naturally Occurring Single Nucleotide Polymorphisms

Figure 2

IL-1β induction of HIV-1 transcription is dependent on basal LTR expression phenotype in TF-1 and U-937 cell clones. TF-1 and U-937 stably transfected cell clones containing the WT, 3T, 5T, or 3T5T LAI LTRs were treated with IL-1β (20 ng/mL) for 24 hours and then analyzed using flow cytometry for their stimulated GFP expression. All experiments were completed in triplicate in three independent experiments. Representative histograms showing levels of GFP expression obtained with the untreated stably transfected cell clone (solid turquoise line), the treated stably transfected cell clone (dashed turquoise line), untreated WT TF-1 and U-937 cells (solid black line), and treated WT TF-1 and U-937 cells (dashed black line) are shown. Designations of nonexpressing (NE), intermediate-expressing (IE), and high-expressing (HE) are determined based on basal levels of LTR-driven gene expression within each clone. (a) LTRs from NE WT, 3T, and 5T TF-1 cells were unable to be induced into driving GFP expression, whereas the cells containing NE 3T5T LTRs were activated following treatment. Additionally, active LTRs could be induced to drive higher levels of GFP expression. (b) LTRs from NE U-937 cells were unable to be induced into driving GFP expression, whereas the cells containing active LTRs could be induced to drive higher levels of GFP expression.

(a)

(b)