Low molecular weight RNAs of post-ribosomal particles: Evidence that the particulate 4-S RNAs comprise a differential population of transfer RNA

Abstract

Low molecular weight, methylated RNA having the electrophoretic mobility of transfer RNA was isolated from 10- to 30-S particulate material of cultured Chinese hamster cell cytoplasm. The nature of the particulate 4-S RNA was investigated. It was found to be methylated to about the same extent as supernatant transfer RNA. Most of it was transfer RNA as judged by its acceptance of AMP from ATP in the presence of tRNA-CMP-AMP pyrophosphorylase or by detailed analysis of its methylated nucleoside composition. The particulate 4-S RNA did not accept amino acids for the formation of aminoacyl-tRNA to the extent of supernatant tRNA and chromatography of particulate 4-S RNA on benzoylated DEAE-cellulose showed a very different elution pattern from that of supernatant tRNA. We conclude that most of the particulate 4-S RNAs comprise a differential population of transfer RNA like material.