Figure 4.

Confirmation of the methylation-deficient status of C subunit mutants by an in vivo radiolabeling methylation assay. (A and B) In vivo ³H-methylation assays were performed as described in MATERIALS AND METHODS on the indicated C subunits (see RESULTS and Table 1 for mutant definitions). Phosphorimager (methylation) and fluorimager (immunoblot) images are shown. Similar results were obtained in at least two independent experiments. The C subunits migrate as doublets in these gels, but whether double or single bands are seen can vary (see details in legend to Figure 1). All lanes in each panel are from the same experiment and were analyzed on the same gel but were not all originally adjacent.