Figure 1

Promoter activity and CpG methylation of HIV LTR. A. Suppression of HIV LTR promoter activity by CpG methylation in vitro. HIV LTR-Luc plasmid, with or without in vitro methylation by SssI methylase, was transiently transfected into Jurkat cells with pRL-tk-Luc plasmid. Representative results of triplicate experiments are presented with standard deviation. Relative luciferase activity was determined by dividing the activity of firefly luciferase by that of renilla luciferase. Three independent experiments gave almost identical results. B. Northern blot analysis of HIV mRNA. Expression of HIV mRNA was detected using HIV LTR probe (upper panel). Molt20-2 is a gift from Prof. T Shiota (Osaka University) and derived form Molt4 infected by HIV Lai. Lower panel, photograph of ethidium bromide stained samples. C. Results of CpG methylation analysis of integrated HIV provirus LTRs of chronically infected cells lines. Single line represents the results of one plasmid clone analyzed. Upper panel, Schematic map of the CpG sites in the U3 region of HIV-1 IIIB LTR. Closed and open circles indicate methylated and unmethylated CpG sites, respectively.