Biological decay of the 5′-triphosphate termini of the RNA of E. coli

Abstract

EXPERIMENTS in vitro and in vivo have shown that nascent RNA chains have 5′-triphosphate termini and that the 5′ terminal nucleosides are either adenosine or guanosine^1–3. Little is known about the fate of these termini. It is known that in Escherichia coli mRNA is degraded rapidly⁴, and that the nascent precursors of ribosomal and tRNA mature—a process involving trimming at the 5′ end^5–7—and then have only one phosphate group on the 5′ end^7,8. It seems, therefore, that the 5′-triphosphate termini should disappear as a result of mRNA decay and stable RNA maturation. We have examined the disappearance of triphosphate termini from E. coli RNA and found that they decay at a rate approximately one-half of that of the bulk of the unstable RNA.