FIG. 1.

Expression of p50- and p18-cyclin E following radiation. Multiple-myeloma IM-9 (A), U-266 (B), and lymphoma Molt-4 (C) cells were irradiated (20, 20, and 4 Gy, respectively) and lysed at the indicated times, and 20 μg of protein was subjected to SDS-12% PAGE as described in Materials and Methods. Western blot analyses were performed using rabbit anti-cyclin E (C-19) and mouse anti-β-actin primary antibodies, the corresponding HRP-conjugated secondary antibodies, and ECL reagent used as a chemiluminescent agent. The full-length cyclin E, which is 50 kDa and is found predominantly in both normal and tumor cells, is the EL form (i.e., the 15-amino-acid elongated variant of cyclin E [46, 49]). Abbreviations: Cyc E, cyclin E; p18, novel cyclin E-derivative.