Fig. 2. (A) TDs and punctate plasmid transcription sites represent nascent transcription. HeLa cells were transiently transfected with pHIV-ß and plasmid transcription was double-labelled by RNA in situ hybridisation using probes to the ß-globin first or second intron (left panel) and 3' flank (middle panel). The RNA signals colocalised, as indicated by the yellow colour in the overlay images (right panel). Bars, 1 µm. (B) Plasmid TDs localise adjacent to the interchromatin granule clusters (IGCs) and the PML bodies. HeLa cells were transiently transfected with pHIV-ß and plasmid transcription sites were labelled by RNA in situ hybridisation using probes to the ß-globin first intron (green signals). IGCs were labelled with an anti-SC35 antibody (top panels) and PML bodies were labelled with an anti-PML antibody (bottom panels). TDs were consistently observed adjacent to both IGCs and PML bodies. Bars, 5 µm.