| Abstract: | Studies of the chromatographic behavior of mammalian tRNAs, from several sources, on acylated DBAE-cellulose indicate that species of tRNA Asn , tRNA Asp and tRNA His can be retained on this matrix, while species of tRNA Tyr, tRNA Asn and tRNA Asp are not retained. Treatment of total rat liver tRNA with cyanogen bromide and subsequent chromatography on Aminex A-28 columns demonstrated that these tRNA species might contain Q (or Q*) nucleoside. However, comparable studies of the tRNA isolated from Walker 256 rat mammary tumor tissue demonstrated that this tumor tRNA almost totally lacks the hypermodified nucleosides Q and Q*. In addition, we have found that at least the major species of rat liver tRNA Asn contains the Q nucleoside. These studies indicate that chromatography on the acylated DBAE-cellulose matrix, couple with the analytical ion-exchange chromatography of cyanogen bromide treated and untreated amino-acyl-tRNA can be a valuable technique for the determination of alterations in the Q (or Q*) nucleoside content of the tRNAs isolated from normal and tumor tissues. |
