The plasmid template for production of dsRNA was constructed in the stem-loop
structure for in vivo bacterial expression system. PAZ-dsRNA and PIWI-dsRNA were designed from
the coding sequence of the PAZ domain (396 bp) and 81 bp present only in the PIWI domain of
PemAGO-L, respectively. Two pairs of primers were used for the production of templates to
construct each dsRNA. The first PCR product contains stem and loop region (called sense strand).
The second PCR product contains only the stem that is identical to the stem region of the first PCR
product but inserted in an inverted orientation (called anti-sense strand) into pET-17b vector. The
recombinant plasmids (figure 1) were transformed into Escherichia coli HT115 strain bacterial
host that lacks RNase III activity. The dsRNAs were produced in bacterial system by IPTG
induction. The single-stranded RNA (ssRNA) in the loop region and endogenous RNA were
removed by RNase A treatment after bacterial cells lysis. The dsRNAs were then purified by TRIReagent
® and dissolved in 150 mM NaCl. The concentration of dsRNA was determined by agarose
gel electrophoresis. The dsRNAs were verified by digestion with RNase A and RNase III.