6S RNA - an old issue became blue-green

Area of Science:

• Molecular Biology
• Microbiology
• Genetics

Background:

• 6S RNA regulates transcription in Escherichia coli by binding RNA polymerase.
• Knowledge of 6S RNA function is primarily derived from E. coli studies.
• Homologous 6S RNAs are present in diverse bacteria, including cyanobacteria.

Purpose of the Study:

• To investigate structural and functional conservation of cyanobacterial 6S RNAs.
• To compare cyanobacterial 6S RNAs with their E. coli counterpart.
• To explore the physiological role of 6S RNA in cyanobacteria.

Main Methods:

• Temperature-gradient gel electrophoresis to assess RNA secondary structure.
• Enzymatic hydrolysis and in-line probing for detailed structural analysis.
• Functional assays testing RNA polymerase binding, transcriptional inhibition, and product RNA synthesis.

Main Results:

• Cyanobacterial 6S RNAs exhibit similar thermodynamic profiles and secondary structures to E. coli 6S RNA.
• All tested cyanobacterial 6S RNAs effectively bind E. coli RNA polymerase and inhibit transcription.
• Deletion of 6S RNA in Synechocystis impacted growth on solid media, suggesting a physiological role.

Conclusions:

• Basic functions of 6S RNA are conserved between E. coli and cyanobacteria.
• Minor structural differences in cyanobacterial 6S RNAs may relate to optimal growth temperatures.
• This study provides initial evidence for a physiological role of 6S RNA in cyanobacteria, reflecting regulatory and lifestyle adaptations.