The binding of aminoacyl-sRNA's to ribosomes stimulated by block oligonucleotides.

Abstract

The results presented clearly demonstrate that any trinucleotide sequence within a short messenger chain is potentially capable of coding for the specific binding of an aminoacyl-sRNA. These findings have a bearing on the problem of the initiation of mRNA translation and protein synthesis in vivo, where it seems highly likely that some mechanism which ensures initiation only at a specific point(s) on the mRNA chain must exist. The lack of specificity found in the in vitro binding studies implies that one or more additional components are required for specific initiation. It is possible that an initiator enzyme which normally enables the selection of only one end of the messenger chain is absent in our in vitro binding system. In vivo the polarity of mRNA synthesis or its release from a DNA-protein complex may determine the initiation point for protein synthesis. There may be some chemically distinct feature of the natural mRNA chain which codes for initiation, such as an initiator coding triplet, a sequence of methylated bases, or a terminal phosphate group.