TRANSFER RIBONUCLEIC-ACIDS FROM 11 IMMUNOGLOBULIN-SECRETING MOUSE PLASMACYTOMAS - CONSTANT AND VARIABLE CHROMATOGRAPHIC PROFILES COMPARED WITH THE MYELOMA PROTEIN SEQUENCES

To test whether aminoacyl-tRNAs in plasmacytomas modulate the protein synthesized or reflect the structure of the synthesized protein, the RPC-5 chromatographic profiles of aminoacyl-tRNAs for all 20 amino acids were studied in tRNA prepared from normal mouse liver and 11 plasmacytomas. The patterns of isoaccepting tRNA were compared with the structure of the myeloma protein being synthesized. The elution profiles of aminoacyl-tRNAs for 9 of the amino acids were constant, i.e., they were the same for liver and all plasmacytomas. Significant variability was observed in the profiles of the other 11 families of aminoacyl-tRNAs: Asn, Ser and Try had peaks of isoaccepting tRNAs found in tumors and not in liver; Glu, His and Lys had different patterns of aminoacyl-tRNAs in plasmacytomas which could be distinguished from the elution profile of liver; and Ile, Pro, Thr and Tyr showed pattern variability in only a few of the tumors. Valyl-tRNA uniquely had 1 isoacceptor present in liver but absent in the tumors. This variability probably is associated with different posttranscriptional modification of the tRNAs rather than regulation of individual tRNA genes in response to particular amino acid sequences in secreted myeloma proteins. The lack of correlation of isoacceptors with sequence differences makes the modulation of protein fine structure by tRNA availability unlikely.