FIG. 1.
Prolonged GC treatment induces optimal transcriptional induction of the Tat gene and chromatin remodeling at the −2.5 Tat GRU. (A) RNA FISH analysis of nascent and mature Tat transcripts in H4II cells treated with 10−7 M Dex, or left untreated, for 2 days. To quantify the percentage of activated gene copies, the number of transcription foci in about 200 cells was determined. (B) Chromatin accessibility at the −2.5 Tat GRU as assessed by sensitivity to restriction enzyme cleavage of H4II nuclei and indirect end labeling. “Marker” corresponds to genomic DNA cleaved with XbaI in vitro.