抄録
(1) Incorporation of 14C-leucine into myeloma protein fraction of X5563 plasma cell tumor in C3H mouse was partially inhibited by, actinomycin D. This result suggests the existence of a stable messenger RNA in the tumor cells.
(2) The actinomycin-depressed myeloma protein synthesis could be restored following extracellular treatment with X5563 tumor RNA for 15 hours at 2°C.
(3) Treatment with X5563 tumor RNA for 15 hours at 2°C could induce myeloma protein synthesis in Ehrlich ascites tumor cells. Neither RNase treated RNA of X5563 tumor nor RNA of Ehrlich tumor itself was capable of inducing the myeloma protein.
(4) In present experiments RNA treatments caused the inhibition of protein synthesis in the recipient cells in proportion of the concentration, although it had no inhibitory effect on the oxygen consumption of the cells. So, the ability of RNA restoring or inducing myeloma protein synthesis was expressed by a ratio of myeloma protein fraction to total soluble protein fraction in 14C-leucine incorporation. 14C-leucine incorporated into myeloma protein fraction was determined by the radioactivity in the precipitate with anti-myeloma rabbit serum.
