mRNA Decay in Escherichia coli Comes of Age

Abstract

When Apirion first proposed that mRNA decay in Escherichia coli involves a series of endo- and exonucleolytic events (2), the general working assumption was that the turnover of transcripts is a simple salvage pathway that is necessary for recycling of ribonucleotides. Although experimental data at that time indicated that mRNAs are rapidly degraded (11, 40) and that decay of individual transcripts is independent of length (9), the number and specificities of the enzymes that actually carry out transcript degradation were still open questions. Twenty-nine years and many experiments later, a much different picture has emerged. Not only is the pathway of mRNA decay far more complex than originally envisioned, but it apparently also plays an integral role in regulating the expression of many genes. While many important features of this system remain to be elucidated, this prospective attempts to convey the current state of knowledge. In addition, it focuses primarily on those areas where there are disagreements regarding important features of the mRNA decay process.