Tumor-associated phenylalanyl transfer RNA found in a wide spectrum of rat and mouse tumors but absent in normal adult, fetal, and regenerating tissues.

RPC-5 chromatography was used to examine the phenylalanyl transfer RNA (Phe-tRNA) of 25 normal rat and mouse tissues including adult, fetal, and regenerating liver; whole embryos; and other adult organs. Only a single major isoaccepting Phe-tRNA was found in every case. Phe-tRNA's from 25 transplantable rat tumors and 33 transplantable mouse tumors were similarly examined. Seventeen rat tumors and 10 mouse tumors, of a wide spectrum of histological types, were found to have an additional, tumor-associated Phe-tRNA isoacceptor. This tumor-associated Phe-tRNA was not found in the livers of animals bearing tumors that contained this isoacceptor. Differences in chromatographic behavior between the rat and mouse tumor-associated Phe-tRNA's strongly suggest that they have different structures. Our data suggest that these differences result from different degrees of incompleteness of posttranscriptional modification, most likely at the normally very hypermodified Wye (formerly called Y) base.