PTB Overexpression Is Sufficient to Reverse HIV-1 Latency in Primary Resting CD4<sup>+</sup> T Cells

<div><p>(A) Diagram of expression constructs. The PTB construct contains full-length PTB including a NLS and four RNA recognition motifs (RRM). PTB ser-ala has a single serine to alanine substitution at position 16 in the NES located within the NLS region. PTBT is the 25 kDA isoform which lacks an NLS but contains two intact RRMs.</p><p>(B) Overexpression of PTB and PTB ser-ala is sufficient to upregulate virus production from resting CD4<sup>+</sup> T cells. Purified resting CD4<sup>+</sup> T cells from patients on HAART were transfected with the indicated constructs. Culture supernatants were isolated 72 h post-transfection and analyzed for viral RNA. Dotted line represents the limit of detection of the assay.</p><p>(C) Other cellular proteins that bind HIV-1 RNA cannot induce virus production from resting CD4<sup>+</sup> T cells of patients on HAART. Resting CD4<sup>+</sup> T cells were transfected as described above with empty vector or hnRNP A1 (left panel) and empty vector or La (right panel). HIV-1 RNA levels in the supernatants 72 h after transfection are shown.</p></div>