Figure 3.

Analysis of human PiT1 E₇₀K and PiT2 H₅₀₂A for Na³²P_i uptake and gamma-retroviral receptor function. A-B X. laevis oocytes were injected with H₂O (Mock) or cRNA of the indicated constructs. Three days later, a ³²P_i uptake assay was performed and the ³²P_i uptake in individual oocytes was measured. Data are the mean value of (n) numbers of oocytes ±SEM, see Additional File 2 for data and statistics. Experiments A and B were made independently of each other, and the experiments were repeated and similar results obtained. C CHO K1 cells were transfected with CsCl-purified PiT1- or PiT1 E₇₀K-encoding plasmid or empty vector DNA (Mock). Three independent precipitates were made for each construct. Forty-eight hours after transfection, approx. 8 × 10⁴ 10A1 MLV pseudotypes were added per dish. The average numbers (±SEM) of blue (infected) cells per dish from three dishes receiving independent precipitates are shown, see Additional File 2 for data and statistics. D-E were made in parallel using the same protocol as in (C) with the exception that Nucleobond-purified plasmids encoding PiT2, PiT2 H₅₀₂A, or empty vector DNA were used. The dishes were challenged with approx. 4 × 10⁴ 10A1 MLV pseudotypes (D) or A-MLV pseudotypes (E). The average numbers (±SEM) of blue (infected) cells per dish from three dishes receiving independent precipitates are shown, see Additional File 2 for data and statistics.