Immunoglobulin gene expression in a coupled transcription/translation system from mouse plasmacytoma cell-free extracts.

Mouse plasmacytoma cytoplasmic extracts and sonicated nuclei have been incubated under conditions which resulted in translation and transcription, respectively. When the cell-free systems were combined, incorporation of radioactive precursors into RNA and protein was enhanced and extended. Coupling of transcription and translation was indicted by the inhibition of protein synthesis, and specifically immunoglobulin synthesis, by actinomycin D and alpha-amanitin. When immunoglobulin synthesis was investigated in MOPC-104E cells Which contain both lambda and K mRNAs but secrete only lambda light chains, the extracts synthesized both K and Lambda light chains. These results indicated that the unexpressed MOPC-104E K mRNA could be translated on homologous ribosomes under the appropriate conditions and suggested that postranscriptional controls may play a role in k-chain gene expression in MOPC-104E cells.