FIG. 2.

ZAP-70 expression in Jurkat-derived subclones. (A) Northern blot analysis. Total cellular RNA (30 μg) from Jurkat cells (wild type [WT]), P116 cells, or TF.wild B-lymphoma cells was separated electrophoretically and blotted onto a nitrocellulose membrane. The Northern blot was sequentially hybridized with ³²P-labeled DNA probes for ZAP-70 and GAPDH. (B) Immunoblot analysis. Detergent-soluble proteins from wild-type Jurkat or the indicated Jurkat subclones (see Fig. 1 legend for description of subclones) were separated by SDS-PAGE and immunoblotted with ZAP-70-specific antibodies. The decreased electrophoretic mobility of the kinase-inactive ZAP-70 mutant expressed in DK2 and DK33 cells is due to the presence of the amino-terminal Myc epitope tag.