Messenger RNA Degradation in Bacteria

Decay of messenger RNA (mRNA) is an essential function in bacteria, allowing rapid adjustments in gene expression and replenishing of the ribonucleotide pool. Efficient turnover of intermediates in the mRNA decay process is necessary to avoid nonproductive translation. Certain structural features of an mRNA make it resistant to attack: nucleoside-5'-triphosphate at the 5' end, transcription terminator structure at the 3' end, and ribosome flow down the body of the message. In Escherichia coli, decay proceeds by a combination of endonuclease cleavage and degradation by 3' exonucleases. In Bacillus subtilis, an alternative mechanism occurs, in which decay proceeds from the native 5' end of a message. Endoribonucleases that are involved in initiation of mRNA decay are subject to regulation of gene expression and activity.