FIG 4.

Dox-inducible expression of ZAP isoforms in ZAP KO 293T cells. Stable cell lines with inducible expression of N-terminally RFP-tagged ZAP isoforms were generated in ZAP knockout 293T cells by use of the ePB transposon system. All four ZAP isoforms can be detected by immunoblotting (A) and fluorescence imaging (B). Expected sizes for ZAP isoforms are as follows: 106 kDa for RFP-ZAPS, 119 kDa for RFP-ZAPM, 130 kDa for RFP-ZAPL, and 142 kDa for RFP-ZAPXL. Dox titration was first carried out on one of the cell lines, and 1 μg/ml Dox was used to induce individual ZAP isoforms in all the cell lines. The data are representative of results from 2 independent experiments.