Small RNAs Asserting Big Roles in Mycobacteria

Tuberculosis (TB) is an infectious disease caused by Mycobacterium tuberculosis (Mtb), with 10.4 million new cases per year reported in the human population. Recent studies on the Mtb transcriptome have revealed the abundance of noncoding RNAs expressed at various phases of mycobacteria growth, in culture, in infected mammalian cells, and in patients. Among these noncoding RNAs are both small RNAs (sRNAs) between 50 and 350 nts in length and smaller RNAs (sncRNA) < 50 nts. In this review, we provide an up-to-date synopsis of the identification, designation, and function of these Mtb-encoded sRNAs and sncRNAs. The methodological advances including RNA sequencing strategies, small RNA antagonists, and locked nucleic acid sequence-specific RNA probes advancing the studies on these small RNA are described. Initial insights into the regulation of the small RNA expression and putative processing enzymes required for their synthesis and function are discussed. There are many open questions remaining about the biological and pathogenic roles of these small non-coding RNAs, and potential research directions needed to define the role of these mycobacterial noncoding RNAs are summarized.

Automated summary

Tuberculosis (TB) is an infectious disease caused by Mycobacterium tuberculosis (Mtb), with recent studies revealing the abundance of noncoding RNAs expressed by these bacteria in different growth phases and infection states. These noncoding RNAs include small RNAs and even smaller RNAs, and methodological advances like RNA sequencing strategies and specific RNA probes have advanced the study of these small RNAs. Further research is needed to fully understand the biological and pathogenic roles of these mycobacterial noncoding RNAs.