Regulation of Bacterial Transcription by Small Non-Coding RNAs

Bacteria employ small non-coding RNAs (sRNAs) as versatile regulators of gene expression, primarily by modulating the activity of RNA polymerase and its interaction with sigma factors. These sRNAs, typically 50–300 nucleotides in length, can bind directly to the RNA polymerase holoenzyme or to specific sigma subunits to either inhibit or redirect transcription initiation. The prototypical example, 6S RNA, mimics an open promoter complex to sequester the primary σ^70-holoenzyme during stationary phase, thereby reshaping the transcriptome in response to nutrient limitation and stress. Upon outgrowth, synthesis of short product RNAs (pRNAs) triggers conformational changes in 6S RNA that release RNA polymerase, allowing rapid resumption of growth-related transcription. Another class, exemplified by Ms1 RNA in Actinobacteria, associates with the RNA polymerase core to influence enzyme abundance and transcriptional capacity. These sRNA-based circuits integrate environmental cues with global transcriptional programmes, enabling bacteria to fine-tune stress responses, developmental processes such as sporulation, and adaptive behaviours relevant to pathogenesis and biotechnology. Advances in high-throughput sequencing and structural biology have begun to reveal the breadth of RNAP-interacting sRNAs across diverse taxa, underscoring their universal contribution to bacterial physiology and offering novel targets for antimicrobial strategies.

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Regulation of Bacterial Transcription by Small Non-Coding RNAs publication trend

The graph below shows the total number of articles in regulation of bacterial transcription by small non-coding rnas across all publications each year (not limited to Nature Index journals).

Technical terms

Small non-coding RNA (sRNA): RNA molecule not translated into protein that regulates gene expression post-transcriptionally or by direct interaction with transcription machinery.

RNA polymerase holoenzyme: Multi-subunit enzyme complex comprising the RNA polymerase core and a sigma factor, responsible for promoter recognition and transcription initiation.

Sigma factor (σ): Accessory subunit that directs RNA polymerase to specific promoter sequences, enabling differential gene expression under varying conditions.

6S RNA: A highly conserved bacterial sRNA that mimics an open DNA promoter to bind and regulate the σ^70-holoenzyme during stationary phase.

Ms1 RNA: A structurally related sRNA found in Actinobacteria that binds the RNA polymerase core and influences enzyme levels and transcriptional output.

Product RNA (pRNA): Short transcripts synthesised by RNA polymerase using 6S RNA as template, triggering conformational changes that release the sRNA from the enzyme.

References

1. RIP-seq reveals RNAs that interact with RNA polymerase and primary sigma factors in bacteria. Nucleic Acids Research (2024).
2. Ms1 RNA Interacts With the RNA Polymerase Core in Streptomyces coelicolor and Was Identified in Majority of Actinobacteria Using a Linguistic Gene Synteny Search. Frontiers in Microbiology (2022).
3. Structural and Functional Insight into the Mechanism of Bacillus subtilis 6S-1 RNA Release from RNA Polymerase. Non-Coding RNA (2022).