FIG. 8.

Microinjection of PLC-γ1 SH2-SH2-SH3 inhibits EGF- and PDGF-induced PKC-dependent, but not PKC-independent, activation of c-fos promoter plasmids. Quiescent MDCK cells (A) or NIH 3T3 cells (B) were injected with wtSRE-CAT (unshaded) or mutant pm18 (shaded) plasmids together with GST or PLC-γ1 SH2-SH2-SH3 and incubated at 37°C for 1 h, incubated with EGF (100 ng/ml) or PDGF (20 ng/ml) with or without DAG for 15 h, and then fixed and stained by immunofluorescence. Microinjected cells were identified with an FITC-avidin stain, and CAT was assayed with a polyclonal anti-CAT antibody followed by a TRITC-conjugated antirabbit antibody. The percentage of cells positive for CAT expression was calculated as described in Materials and Methods. Data are means + standard errors of three independent experiments.