Hey everyone!

I want to produce a doublestranded RNA in E. coli for RNAi experiments. In this particular case, my dsRNA should have mismatches between the two strands, so I can distinguish them during processing within my cells, which is why I can't use some of the standard vectors used for this sort of application (L4440, T444T, ...).

This is why I designed a plasmid, which carrys two different T7 transcription units (attached).

Since the E. coli strain we usually use for dsRNA production (HT115 DE3) does not carry any recA (or similar mutations/deletions, as far as I'm aware), I am not afraid of homologous recombination destroying the plasmid inside my production strain, since sense and antisense sequences are very similar.

Does anyone know a E. coli strain that would be suitable for this kind of dsRNA productions because it carrys both, a RNase3-deficiency and some mutation preventing recombination?

I searched for some strain with these attributes, but I didn't find one.