Stability of chromatographic patterns of aminoacyl transfer ribonucleic acid from individual mouse plasmacytomas and variability among different immunoglobulin A producing plasmacytomas and normal organs

Tumor-specific tRNA modifications in mouse plasmacytomas and other tumors

RPC-5 chromatography has been used to analyze the aa-tRNA populations found in normal organs and in various tumors in experimental animals. The most extensively studied animal systems have been mineral-oil-induced mouse plasmacytomas and carcinogen-induced rat hepatomas. Certain aa-tRNA species appear to be tumor-specific, e.g., rat hepatoma phenylalanyl-tRNA1 and plasmacytoma asparaginyl-tRNAs2-4. In addition, one of the tumor-specific peaks of asparaginyl-tRNA can be found in normal livers of animals bearing plasmacytomas at a distant site. Many other significant quantitative and qualitative differences among histologically similar plasmacytomas and between normal tissues and plasmacytomas were observed in the chromatographic patterns of isoaccepting aa-tRNAs for 11 of 20 amino acids. Some of the qualitative differences in chromatographic patterns could be correlated with the tumorous nature of the tissue using computer analysis. The program utilized cluster analysis to compare the RPC-5 patterns of aa-tRNAs from 11 plasmacytomas and two normal tissues for each of the 20 amino acids. The variations in these chromatographic profiles are though to be caused by varying degrees of incomplete synthesis of some of the normally modified nucleosides in tRNAs.

Changes in the serine-specific transfer ribonucleic acid pattern of guinea pig epidermis after corticosteroid treatment

The pattern of serine-specific tRNAs from guinea pig epidermis was determined and compared to that from liver by employing reversed phase chromatography on total tRNA preparations aminoacylated with 3H- or 14C-serine. Five tRNAserS (I-V) were found, two of which, tRNAserI and tRNAserV, appear to be "typical" for epidermis and in so far probably reflect in some way metabolic peculiarities of epidermal cell differentiation. This hypothesis was further corroborated by showing that the locally applied corticosteroid triamcinolon selectively increases tRNAserI and tRNAserV 2-3-fold. The implications of these findings were discussed in detail.

Transfer ribonucleic acids from eleven immunoglobulin-secreting mouse plasmacytomas. Constant and variable chromatographic profiles compared with the myeloma protein sequences

In order to test the concepts that aminoacyl-tRNAs in plasmacytomas may on the one hand modulate the protein synthesized or on the other hand 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 nine 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: asparagine, serine and tryptophan, had peaks of isoaccepting tRNAs found in tumors and not in liver; glutamic acid, histidine and lysine, had different patterns of aminoacyl-tRNAs in plasmacytomas which could be distinguished from the elution profile of liver; and isoleucine, proline, threonine and tyrosine, showed pattern variability in only a few of the tumors. Valyl-tRNA uniquely had one isoacceptor present in liver but absent in the tumors. This variability is thought to be 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. Similarily, the lack of correlation of isoacceptors with sequence differences makes the modulation of protein fine structure by tRNA availability unlikely.