Co-transcriptional folding of nascent RNA is one of the characteristic processes for the functionalization of nascent RNAs through RNA conformational dynamics. In this research project, we are quantitatively analyzing the effect of RNA conformational dynamics on gene expression. For example, riboswitches recognize specific target molecules during the transcription reaction and regulate gene expression through conformational transition due to target binding. By accumulating knowledge of the functionalization mechanisms of the RNA conformational dynamics that control gene regulation, it will become possible to rationally design artificial molecules that enable regulation of the conformational dynamics and gene expression. We consider that targeting RNA conformational dynamics is a promising approach for the development of novel therapeutic materials.