Induction of vimentin synthesis in mouse myeloma cells MPC-11 by 12-0-tetradecanoylphorbol-13-acetate.

Mouse myeloma cells (MPC-11 cell line) known to lack intermediate filaments were treated with the phorbol ester 12-0-tetradecanoylphorbol-13-acetate (TPA). Asynchronous cell cultures were screened for vimentin by indirect immunofluorescence microscopy, whole cell lysates derived from such cultures by immunoblotting using goat antiserum to vimentin. The minimum TPA concentration sufficient for the induction of vimentin synthesis was found to be 3 X 10(-9) M; substantially larger amounts of vimentin could be detected after treatment of cells with TPA at a concentration of 3 X 10(-8) M. At each effective TPA concentration tested, the maximum level of vimentin was reached after 18 to 24 h; it was dependent on the TPA concentration. In addition, vimentin synthesis was demonstrated employing two-dimensional polyacrylamide gel electrophoresis in combination with either fluorography or immunoblotting and autoradiography. Vimentin purified from TPA-treated MPC-11 cells as well as a protein species in whole lysates from cells labelled with [35S]methionine after TPA treatment for at least 2 h comigrated with vimentin isolated from Ehrlich ascites tumor cells. The fact that only poly(A) +RNA from TPA-treated MPC-11 cells was able to direct vimentin synthesis in vitro suggests that in MPC-11 cells vimentin production is regulated at the transcriptional level.