(A) Scheme of Tat showing the position of its domains (AD, RBD and Ct) along with the location of the mutated residues. (B) Western blots of Jurkat CD4+ T cell lines expressing GFP, wild-type Tat or non-functional mutants (C22A, K50Q, R52R53K) (D'Orso et al., 2012). Cells from panel (B) were used in ChIP assays to analyze the occupancy of GFP, Tat or the non-functional mutants at class I TSG promoters (C), class II TSG promoters (D), class I TDG promoters (E) and class II TDG promoters (F). Values representing the average of three independent experiments (mean ± SEM; n = 3). Cells from panel (B) were used to isolate total RNA and the expression of class I TSG (G), class II TSG (H), class I TDG (I) and class II TDG (J) was measured by qRT-PCR, normalized to RPL19, and plotted as fold RNA change over the GFP line arbitrarily set at 1 (mean ± SEM; n = 3). AD, activation domain; ChIP-seq, chromatin immunoprecipitation sequencing; Ct, C-terminal domain; GFP, green fluorescent protein; qRT-PCR, quantitative real time polymerase chain reaction; RBD, RNA-binding domain; TDG, Tat downregulated genes; TSG, Tat stimulated genes.