Primer extension analysis of tRNA gene transcripts synthesized in vitro and in vivo.

The primer elongation method has been adapted to analyze tRNA gene transcripts. The primer used to direct cDNA synthesis from a corresponding tRNA template, in the presence of AMV reverse transcriptase, was a restriction fragment, or a synthetic oligonucleotide, containing exclusively coding nucleotides of a tRNA gene. This method not only allows one to identify the exact 5'-end of mature tRNA, but also 5'-ends of primary transcripts are readily determined. Further, analysis of tRNAs synthesized in vitro, as well as tRNAs produced in vivo in homologous and heterologous organisms can be studied. Purification of the tRNAs questioned, from bulk tRNA, is not necessary.