HA-CycT1-V107E mutant enforces repression of HIV transcription. a) J-LTR-Tat-BFP control cells or J-LTR-Tat-BFP cells that stably express either HA-CycT1-wild type, or HA-CycT1-V107E (J-LTR-Tat-BFP/HA-CycT1-wild type; J-LTR-Tat-BFP/HA-CycT1-V107E) were activated with TNFα 24 hr. post activation cells were washed and further maintained for additional two weeks. At the indicated time points post activation, cells were analyzed for their LTR-BFP expression by FACS. b) J-LTR-Tat-BFP cells that stably express HA-CycT1-V107E (J-LTR-Tat-BFP/HA-CycT1-V107E) were activated with TNFα and cells were maintained for additional growth. At the indicated time points post activation, BFP expression was monitored by FACS. At day 35-post initial activation, cells were again activated with TNFα. Cells were maintained for additional 25 days (60 days post initial activation), during which, HIV-LTR-BFP expression was measured by FACS.