Translation-Independent Localization of mRNA in E. coli

Abstract

Understanding the organization of a bacterial cell requires the elucidation of the mechanisms by which proteins localize to particular subcellular sites. Thus far, such mechanisms have been suggested to rely on embedded features of the localized proteins. Here, we report that certain messenger RNAs (mRNAs) in Escherichia coli are targeted to the future destination of their encoded proteins, cytoplasm, poles, or inner membrane in a translation-independent manner. Cis-acting sequences within the transmembrane-coding sequence of the membrane proteins are necessary and sufficient for mRNA targeting to the membrane. In contrast to the view that transcription and translation are coupled in bacteria, our results show that, subsequent to their synthesis, certain mRNAs are capable of migrating to particular domains in the cell where their future protein products are required.

The compartmentalized vessel

“…In line with that, several bacterial mRNAs were shown to localize near the chromosomal loci from which they are expressed. 24 In a recent publication in Science, 25 we showed that, contrary to the general thinking in the field, bacterial mRNAs are capable of migrating to particular positions in the cell, where their future protein products are required. 25 Our results were based on imaging of live and fixed cells and were validated by a biochemical approach.…”

“…24 In a recent publication in Science, 25 we showed that, contrary to the general thinking in the field, bacterial mRNAs are capable of migrating to particular positions in the cell, where their future protein products are required. 25 Our results were based on imaging of live and fixed cells and were validated by a biochemical approach. Thus far, we followed the localization of bacterial mRNAs that code for proteins that localize to the cytoplasm, the inner membrane, or the poles (Fig.…”

“…This conclusion emerged from a set of experiments in which we uncoupled transcription and translation by different approaches and demonstrated that targeting is a property of the mRNA. 25 Therefore, the coupling between transcription and translation, a hallmark of the prokaryotic kingdom, is not an absolute requirement, although de facto the two processes can co-occur in bacterial cells. An important and far-reaching conclusion is that the mechanistic basis for separating transcription and translation has developed in the primitive bacterial cells and did not co-evolve with the nucleus of the eukaryotic cell.…”

Beyond ‘furballs’ and ‘dumpling soups’ – towards a molecular architecture of signaling complexes and networks

“…Site-specific and hence asymmetric mRNA localization was first observed for b-actin mRNA in ascidian embryos [48]. Recently targeting of mRNA was also shown in Escherichia coli, challenging the view of coupled transcription and translation in prokaryotes [49]. In mammals, mRNA localization has been observed and extensively researched in nerve cells with their often very long extensions [50].…”

Subcellular localization of bacteriophage PRD1 proteins in Escherichia coli

“…Also localization signals can be found in certain bacterial proteins, similarly to their eukaryotic analogs (Russell and Keiler, 2007). Correspondingly, there is evidence of subcellular localization of certain mRNA transcripts correlating with the localization of their protein products (Nevo-Dinur et al, 2011). Yet another mechanism for protein positioning was brought up by the discovery of cytoskeletal proteins in bacteria (Vats et al, 2009).…”