How does sub-cellular localization affect the fate of bacterial mRNA?

Recently a number of seminal studies have revealed that both sequence and spatio-temporal factors govern RNA decay in bacteria, which is crucial for regulation of gene expression. Ribonucleases have been described that not only exhibit sequence preferences, but also are sub-cellularly localised. Furthermore, the RNA itself is distributed in an organised manner and does not diffuse freely or randomly within the bacterial cells. Thus, even within the sub-micrometer distances of the bacterial intra-cellular space, the positions of the enzymes and their substrates are kept in check. Adding to this complexity is the secondary structure and sequence specificity that many, perhaps all, ribonucleases exhibit, including those that are responsible for "general" RNA degradation. In this review, the implications of these novel findings are discussed and specific examples from Staphylococcus aureus are analysed.