Post-transcriptional control in the polycistronic operon environment: studies of the atp operon of Escherichia coli.

Post-transcriptional control mechanisms assume special significance in polycistronic operons. Differential gene expression in the atp operon of Escherichia coli is primarily attributable to translational control and, to a lesser extent, to control of mRNA stability. At the same time, the polycistronic environment influences, to varying degrees, the relative importance of the different types of post-transcriptional control. The present article briefly reviews more recent results obtained through studies of the atp operon. Investigations of the pathway and kinetics of mRNA decay have yielded new information about the role of degradative mechanisms in the overall scheme of control. Moreover, translational coupling has been shown to feature as a major form of interaction between the atp genes. The relevance of these and other data is discussed in the wider context of the post-transcriptional control mechanisms generally available to E. coli.