Small and Smaller-sRNAs and MicroRNAs in the Regulation of Toxin Gene Expression in Prokaryotic Cells: A Mini-Review

Abstract

Non-coding small RNAs (sRNAs) have been identified in the wide range of bacteria (also pathogenic species) and found to play an important role in the regulation of many processes, including toxin gene expression. The best characterized prokaryotic sRNAs regulate gene expression by base pairing with mRNA targets and fall into two broad classes: cis-encoded sRNAs (also called antisense RNA) and trans-acting sRNAs. Molecules from the second class are frequently considered as the most related to eukaryotic microRNAs. Interestingly, typical microRNA-size RNA molecules have also been reported in prokaryotic cells, although they have received little attention up to now. In this work we have collected information about all three types of small prokaryotic RNAs in the context of the regulation of toxin gene expression.

Keywords: microRNAs; non-coding small RNAs; prokaryotes; toxin gene expression.

Figure 1

Schematic presentation of the three groups of small non-coding RNAs: (a) cis-encoded, (b) trans-encoded, and (c) microRNA-size molecules involved in the regulation of toxin gene expression in prokaryotic cells. Regulatory non-coding RNAs are shown in grey, whereas target mRNAs are shown in black. Size ranges of the respective types of non-coding RNAs are indicated in brackets and cover lengths most frequently reported in the literature.