Riboswitch in Gene Expression Regulation

Riboswitch is a growing interest in the research of gene expression regulation in recent years. Located in the untranslated regions ( UTR ) of mRNAs,the riboswitch directly responses to signals and changes its stem-loop structure to regulate the expression of the downstream gene at the transcription or post-transcription level. Both the signal sensing and conformational changing processes of riboswitches are independent of protein factors. Four classes of riboswitches are categorized based on their sensed signals, which include small-molecule metabolites,metal ions,environmental factors ( temperature,pH ) ,and uncharged tRNA sensitive riboswitches. The most interested class of riboswitches which has the largest number of members is the ones to sense small-molecule metabolites. As more riboswitches are being identified, their significance in molecular evolution and environmental adaptation will be better understood,and could be used as helpful tools for basic biological research or industrial drug development.