Effect of siSETDB1 on HIV-1 progeny formation. Log phase HLM-1 cells were electroporated with siSETDB1 and siHP1 for 48 hrs. Cells were subsequently removed and incubated with Tat for 4 hrs at 37°C in RPMI without serum. Cells were then plated in complete media for 6 days at 37°C and supernatants were process for RT activity. A) The effect of purified Tat protein on HLM-1 activation (lane 2) and subsequent super-activation with siSETDB1 and Tat protein in HLM-1 cells (lane 3). Lane 4 was with siHP1 and lane 5 with siCDK scrambled RNA. B) Western blot of transfected cells for SETDB1, HP1 and actin. Cell extracts were processed post siRNA transfection and western blotted for various proteins. For the actin westerns, Lane 1 is from siSETDB1 treatment and lane 2 is from siHP1 treatment.