Compositions and methods for the production and delivery of double stranded rna

An engineered dsRNA expression construct comprising:

• a. a promoter;
• b. a dsRNA encoding region positioned transcriptionally downstream of the promoter, wherein the dsRNA encoding region comprises a first, sense-oriented, nucleotide sequence, which substantially corresponds to a target sequence, a second, anti-sense-oriented nucleotide sequence, which is substantially complementary to the target sequence, and a third nucleotide sequence, which is flanked by the first and second nucleotide sequences and which encodes one or more nucleotides of a loop-region of an RNA transcript;
• c. a first transcription terminator sequence, positioned 3′ to the dsRNA encoding region;
• and
• d. a second transcription terminator sequence, positioned 3′ to the first transcription terminator, wherein the dsRNA encoding region, first transcription terminator and second transcription terminator are operably linked to the promoter.