Figures & data
Figure 1. Tandem riboswitches occurring in nature. (A) In the glycine gcvT-5′UTR of B. subtilis and V. cholerae 2 glycine aptamers control a single expression platform.Citation5 (B) Two consecutive TPP riboswitches regulate transcription termination in the tenA-5′UTR of B. anthracis.Citation10 (C) In the bhmT-5′UTR of Pelagibacter ubique a transcriptional riboswitch is followed by a translational riboswitch both controlling gene expression in response to SAM.Citation9 (D) The metE-5′UTR of B. clausii harbors 2 riboswitches that regulate transcription termination independently depending on 2 chemical inputs.Citation10 Revised from reference.Citation47 RNAP: RNA polymerase, TPP: thiamine pyrophosphate, SAM: S-adenosylmethionine, AdoCbl: adenosylcobalamin, fourU: fourU motif, SD: Shine-Dalgarno sequence, AUG: translational start codon.
Figure 2. Synthetic tandem riboswitches. (A) The theophylline aptamer domain was coupled to an expression platform resulting in the first synthetic transcriptional on switch. (B) An RNA chimera consisting of aptamers and expression platforms from different riboswitches was designed without the need of a communication module. (C) An aptazyme was constructed by fusing the hammerhead ribozyme to the TPP or theophylline aptamer, respectively. (D) The temperature responsive fourU RNAT hairpin was substituted against hairpin III of the hammerhead ribozyme leading to temperature dependent mRNA cleavage. (E) Tandem arrangement of riboswitch and RNAT leads to transcriptional and translational control by the two inputs ligand binding and temperature sensing. (F) An RNAT is integrated into a riboswitch aptamer resulting in a temperature controlled riboswitch. RNAP: RNA polymerase, TPP: thiamine pyrophosphate, Theo: theophylline, fourU: fourU motif, SD: Shine Dalgarno sequence, AUG: translational start codon. Positions of inserted spacers or communication modules are labeled with orange boxes.
