Polyribosomes and unstable messenger RNA: a stochastic model of protein synthesis

Abstract

A stochastic model based on tape theory of mRNA function is developed. It is assumed that (i) transcription, translation as well as sequential degradation of mRNA proceed in a 5'- to 3'-end direction and that all the three processes can go on simultaneously, (ii) inactivation of 5'-end by an exonuclease (either free or ribosome-bound) is a random process and (iii) the average distance between adjacent ribosomes is constant. Theoretical consequences of the model such as decay of mRNA and its relationship with protein synthesis, size-distribution of polyribosomes, sedimentation profile of rapidly labelled RNA, association of nascent protein with polyribosomes and bacterial enzyme induction, are discussed in the light of information available in literature.