[Translation of MOPC 21 plasmacytoma cell mRNA in a cell-free wheat germ system].

A wheat germ cell-free system was used for translation of kappa-chain IgG1 messenger RNA isolated from mouse plasmacytoma MOPC 21 cells polysomes. The system was optimised for a number of ingredients of the incubation mixture. Incorporation of labelled amino acids in polypeptides was shown as a function of K+, Mg2+, exogenous mRNA concentration and time, mRNA was purificated by two successive oligo (dT)-cellulose chromatographies and two successive sucrose gradient centrifugations or polyacrylamide gel electrophoresis. Different fractions of poly(A)-RNA stimulated protein synthesis 20--30-fold in a wheat germ cell-free system. Analysis of the translation product of 14 and 16S mRNA by SDS-polyacrylamide gel electrophoresis revealed polypeptide comigrating with the authentic L-chain IgG1 and specifically precipitating by an antiserum to mouse IgG and L-chain IgGl (MOPC 21). The 18 and 28S mRNA fractions directed the synthesis of polypeptides with molecular weight up to 50 000 dalton. Immunospecific translation product of the 18 and 28S mRNA contain both L- and H-chains.