Figure 4.
Location (a) and activity (b) of various versions of PGK inducibly expressed in procyclic forms. Cultures (10 ml) initiated at 2 × 105 cells/ml in the presence or absence of 5 μg/ml tetracycline were grown for 48 h; aliquots of 107 cells were then subjected to cell fractionation with digitonin. S, supernatant; P, pellet. The PGKC cell line was initiated at 9 × 105 cells/ml because the cells grow slightly more slowly. (a) Western blot of TCA-precipitated protein using anti-PGKC antibody. (b) Enzyme activities were measured for fractions equivalent to 2 × 106 cells. Results were calculated relative to the supernatant fraction of the control cells without tetracycline, set to 100%, and are the mean from two independent experiments. Cell lines contained different inducible PGK coding regions followed by the ACT 3′ UTR.