A method for the isolation of specific tRNA precursors.

tRNA affinity chromatography, based on complex formation between tRNAs with complementary anticodons, has been applied to the isolation of specific tRNA precursors. When [32P]RNA, isolated from an Escherichia coli strain containing a thermolabile ribonuclease P, was chromatographed on resin-bound yeast phenylalanine tRNA, precursor tRNAGlu (possessing the complementary anticodon) was specifically retained. Likewise, precursor tRNAPhe was isolated from a column of resin-bound E. coli glutamate tRNA. Both precursor tRNAs isolated were monomeric and may be processed products of an originally larger RNA precursor. Both tRNA precursors contain additional nucleotides beyond the 5'-end of the mature tRNA and have all modified bases found in mature tRNA. The method can be extended to isolate other tRNA precursors by affinity chromatography with different tRNAs. Since the principle of complementary anticodon interaction is not restricted to any particular organism, specific precursor tRNAs from other sources may also be isolated in this way.