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Protein expression with T7 promoter - (Dec/29/2009 )

Hi all,

Many of us use the E. coli BL21 (DE3) strain to express cloned genes that have a T7 promoter.

DE3 strains are lysogenic for a λ prophage that contains an IPTG-inducible T7 RNA polymerase.

My question is: what if I would like to express my protein in bacteria other than E. coli? (Shigella in my case). Are there similar commercially available Shigella strains? Can I produce one on my own? What happens if I just clone the T7 RNA polymerase gene and transform it to Shigella cells? Does this make sense...?


Since Shigella is closely related to E. coli it might be possible to use the lysogenization kit from Novagen to make your own DE3-shigella strain.

You can check the sequence need the attB site for integration of the lambda-phage ...otherwise it would not work.