試題詳解

35. Riboswitches are regulatory elements built into mRNA. Which of the following descriptions about the riboswitch is not correct?
(A) One common form of riboregulation in bacteria is the use of ribonucleic acid sequences encoded within mRNA that directly affect the expression of genes encoded in the full transcript.
(B) Riboswitches are trans-acting elements.
(C) Riboswitches are defined as mRNA elements that bind ligands and regulate mRNA expression by forming alternative structures in response to this ligand binding.
(D) Riboswitches are most often located in the 5' UTR of bacterial mRNA. There they regulate the occlusion of signals for transcription attenuation or translation initiation.
(E) However, in some eukaryotic mRNA, the thiamine pyrophosphate (TPP) riboswitch regulates splicing at the 3' end.