FIGURE 3.

Mutation of the RXL motif in SAMHD1 does not affect the levels of SAMHD1 mRNA transcripts. HEK293T cells were transfected with either 0.25 or 2.5 μg of plasmid DNA expressing WT or mutant SAMHD1, and total cellular RNA was extracted at 6 or 24 h post-transfection (hpt). RNA input was normalized for cDNA synthesis, and these products were utilized in quantitative PCR using SAMHD1 specific primers. A and B, Relative SAMHD1 mRNA levels for WT, RL → AA, RL → KV, and RLF → AA mutants are shown at 6 hpt (A) or 24 hpt (B), respectively. C and D, relative SAMHD1 mRNA levels for WT, F → W, and F → K mutants are shown at 6 hpt (C) or 24 hpt (D), respectively. GAPDH was used to normalize quantification, and Renilla luciferase activity was used as an internal control to normalize transfection efficiency. The data shown are n = 2 for a single experiment and are representative of three independent experiments.