Bacterial small RNA

Bacterial small RNA

Bacterial small RNAs (sRNAs) are a class of non-coding RNA molecules found in bacteria that play crucial roles in the regulation of gene expression. These molecules are typically 50 to 500 nucleotides in length and are involved in various cellular processes, including stress response, metabolism, and pathogenesis.

Structure and Function

Bacterial sRNAs are diverse in their structure and function. They can be classified based on their mode of action:

• Cis-encoded sRNAs: These sRNAs are transcribed from the opposite strand of their target mRNA and have perfect or near-perfect complementarity to their target. They typically regulate gene expression by base-pairing with their target mRNA, leading to either degradation or inhibition of translation.

• Trans-encoded sRNAs: These sRNAs are encoded at loci distinct from their target mRNAs and have limited complementarity. They often require the assistance of RNA chaperones, such as the Hfq protein, to facilitate their interaction with target mRNAs.

Mechanisms of Action

Bacterial sRNAs regulate gene expression through several mechanisms:

• Base-pairing with mRNA: sRNAs can bind to complementary sequences in mRNA, affecting its stability and translation. This can lead to either degradation of the mRNA or inhibition of ribosome binding.

• Protein sequestration: Some sRNAs bind to proteins, altering their activity. For example, sRNAs can sequester CsrA, a global regulator protein, thereby modulating its regulatory effects.

• Modulation of transcription: Certain sRNAs can influence transcription by interacting with RNA polymerase or transcription factors.

Biological Roles

Bacterial sRNAs are involved in a wide range of biological processes:

• Stress response: sRNAs help bacteria adapt to environmental changes by regulating stress response genes.

• Virulence: In pathogenic bacteria, sRNAs can regulate genes involved in virulence, aiding in infection and survival within the host.

• Metabolic regulation: sRNAs play roles in the regulation of metabolic pathways, ensuring efficient use of resources.

Research and Applications

The study of bacterial sRNAs is a rapidly growing field. Understanding sRNA function can lead to new insights into bacterial physiology and pathogenesis. Additionally, sRNAs have potential applications in biotechnology and medicine, such as the development of novel antimicrobial strategies.

Also see

• Non-coding RNA
• Gene regulation
• RNA chaperone
• Hfq
• CsrA