Table 1.

Overview of novel approaches having been established for microbial production of RNA molecules

Approach	Target RNA	Bacterial strain	Vector	Promoter	Purification method	Yield (mg/L culture)	References
tRNA scaffold	Various	E. coli JMlOlTr E. coli BL21 (DE3)	pBSTNAV derivative or pET23b	lpp or T7	PAGE, affinity or ion exchange FPLC	Tens	Nelissen et al. 2012; Ponchon et al. 2009; Ponchon and Dardel 2007
rRNA scaffold	Aptamers, sRNAs	E. coli JM109 (DE3)	pCV and pCR derivatives	rrnB P1/P2	Gel electrophoresis	2–8 mg/g cells	Liu et al. 2010
tRNA/pre-miRNA carrier	Various	E. coli HST08 and DH5a	pBSTNAV	lpp	Spin column, FPLC methods, etc.	Tens	Chen et al. 2015; Ho et al. 2018; Li et al. 2015; Petrek et al. 2019
ELVd RNA carrier	Aptamer, sRNA	E. coli BL21 or derivative	P15tRnlSm andpLELVd-BZB	lpp	PAGE, FPLC	~150 (estimated; total ELVd RNAs)	Daros et al. 2018
siRNA binding protein (pl9)	siRNA	E. coli T7 Express Iq (BL21derivative)	pRSF-GST-p19-His and pCDF-GST-p19-His	tac (p19) and T7 (siRNA)	Affinity chromatograph and anion exchange HPLC	~0.04	Huang et al. 2013
Using RNase III-deficient C. glutamicum	U1A*-RNA diapl *-dsRNA	C. glutamicum 2256LΔrnc	pVH2	F1	(Not reported or demonstrated)	Up to 75–300	Hashiro et al. 2019a; Hashiro et al. 2019b