[Application of synthetic small regulatory RNAs in synthetic biology]

Synthetic biology has brought enormous impacts to the advancement of agriculture, energy, manufacturing and medicine by redesigning existing natural systems or creating biological elements, modules and systems to endow life with new functions. The precise, quantitative and efficient regulation of biological elements, modules and systems is critical for controlling living systems. Bacterial small regulatory RNAs are a class of functional molecules with a length of 50-300 nt and usually do not translate into proteins. They play an irreplaceable role in environmental stress response, metabolic adaptation and bacterial virulence control. In recent years, synthetic small regulatory RNAs have been designed based on natural small RNAs and were used to effectively inhibit or activate target genes and even pathways. Synthetic small regulatory RNAs have broad application advantages in synthetic biology because of their small size, high flexibility, programmability, easy design and little metabolic burden on host cells. To better understand the synthetic small regulatory RNAs and promote its application, this review summarized several synthetic small RNA systems and their representative applications in synthetic biology. Finally, future optimization directions were prospected.