FIGURE 3.

TAT PTD-Cre transduction occurs in the absence of glycosaminoglycans and SAs in parental CHO and glycan-deficient cell lines. A, TAT PTD-Cre recombination in CHO-K1 and derivative glycan mutant pgsA and Lec2 cells with a stably integrated Lox-STOP-Lox-GFP expression construct. Cells were treated with purified recombinant TAT PTD-Cre fusion protein or control recombinant Cre (no TAT PTD) at the indicated concentrations for 1 h, followed by trypsinization and replating. Flow cytometry was performed at 24 h after Cre addition. As indicated, control cells were treated with cytochalasin D to inhibit macropinocytosis for 1 h at 37 °C immediately preceding and during TAT PTD-Cre treatment. B, photomicrographs of TAT PTD-Cre recombination-induced GFP expression in parental and glycan mutant cells with stably integrated LSL-GFP construct. C, FACS profiles of representative samples from the experiment in A. WT, wild-type.