Figure 1From: A single point mutation in cyclin T1 eliminates binding to Hexim1, Cdk9 and RNA but not to AFF4 and enforces repression of HIV transcriptionAnalysis of HIV Tat transactivation in murine cells upon expression of HA-CycT1 mutants. 3T3 murine cells were co-transfected with the HIV-LTR-Luciferase reporter gene, HIV Tat and each of the HA-CycT1 mutants expressing plasmids. 48 hr. post transfection cells were harvested and their Tat-dependent luciferase activities were measured. Luciferase readings were normalized to Renila expression and data are presented relative to the readings obtained in cells that expressed human HA-CycT1-wild-type – set to 100 (assays were measured relative to cells that expressed HIV LTR-Luc reporter and Tat alone). HA-CycT1 mutants are divided to four groups according to their binding to Cdk9 and Hexim1 (Table 1). Asterisks mark specific HA-CycT1 mutants that were severely impaired in their ability to rescue Tat transactivation. Results are representative of the mean value of triplicate wells; error bars show ± SEM.Back to article page