Groupe ARN/RNA Group, Département de Biologie, Faculté des Sciences, Université de Sherbrooke, Sherbrooke, Québec, Canada.
PLoS Genet. 2011 Jan 20;7(1):e1001278. doi: 10.1371/journal.pgen.1001278.
Many bacterial mRNAs are regulated at the transcriptional or translational level by ligand-binding elements called riboswitches. Although they both bind adenine, the adenine riboswitches of Bacillus subtilis and Vibrio vulnificus differ by controlling transcription and translation, respectively. Here, we demonstrate that, beyond the obvious difference in transcriptional and translational modulation, both adenine riboswitches exhibit different ligand binding properties and appear to operate under different regulation regimes (kinetic versus thermodynamic). While the B. subtilis pbuE riboswitch fully depends on co-transcriptional binding of adenine to function, the V. vulnificus add riboswitch can bind to adenine after transcription is completed and still perform translation regulation. Further investigation demonstrates that the rate of transcription is critical for the B. subtilis pbuE riboswitch to perform efficiently, which is in agreement with a co-transcriptional regulation. Our results suggest that the nature of gene regulation control, that is transcription or translation, may have a high importance in riboswitch regulatory mechanisms.
许多细菌的 mRNA 在转录或翻译水平上受到配体结合元件的调节，这些元件被称为核糖开关。虽然它们都结合腺嘌呤，但枯草芽孢杆菌和创伤弧菌的腺嘌呤核糖开关分别通过控制转录和翻译而有所不同。在这里，我们证明，除了转录和翻译调节的明显差异之外，这两种腺嘌呤核糖开关都表现出不同的配体结合特性，并且似乎在不同的调节机制下（动力学与热力学）发挥作用。虽然枯草芽孢杆菌 pbuE 核糖开关完全依赖于腺嘌呤的共转录结合才能发挥作用，但创伤弧菌 add 核糖开关可以在转录完成后结合腺嘌呤，并且仍然可以进行翻译调节。进一步的研究表明，转录的速率对于枯草芽孢杆菌 pbuE 核糖开关的高效运行至关重要，这与共转录调节一致。我们的结果表明，基因调控控制的性质，即转录或翻译，可能在核糖开关的调节机制中具有重要意义。
