RNA precursor molecules and ribonucleases in E. coli

The post-transcriptional alteration of one E. coli RNA species (tyrosine tRNA) by nucleases is now understood in some detail. Knowledge of this pathway has allowed us to speculate on the nature and control of the processing of other E. coli RNA species by the combined attack of endo- and exo-nucleolytic ribonucleases. A review of the properties of known E. coli ribonucleases has led us consider which of these activities might be capable of functioning together in different pathways. The control of these nuclease activities (singly or in groups) may be exerted through structural transitions of RNA substrates or through ionic or protein cofactors.