Expression of PKC isoforms in selected TF-1 transfectants. TF-1 cells were transfected with appropriate plasmids containing either PKC or δ cDNA inserts. Transfectants were selected in the antibiotic G418. Isoform overexpression was determined either with (+) or without (-) induction with 70 μmol/L zinc acetate for 18 hours. Enzyme overexpression was detected by immunoblotting after proteins were separated by electrophoresis in a 10% SDS polyacrylamide gel. Results from immunoblots of  isoform transfected cells probed with affinity purified rabbit polyclonal antibodies against murine PKC and cross-reacting with the human protein (GIBCO/BRL) are shown in (A), and results from δ transfected cells probed with antipeptide monoclonal antibodies recognizing both murine and human PKCδ (Transduction Laboratories) are shown in (B). Levels of overexpression were determined by digitizing ECL film images on the blots and analyzing the images with the 1D Gel Scan program (Scanalytics). Levels of PKC overexpression between  and δ transfectants cannot be compared in this figure because it is a composite of immunoblots from two different experiments.