METHOD FOR THE PRODUCTION OF SEAMLESS DNA VECTORS

The present invention relates to a method for in vivo production of seamless DNA vectors in E. coli, said seamless DNA vectors comprising a DNA sequence of interest and a phage lambda integrase recombination sequence. The method comprises providing an E. coli strain encoding a mutant phage lambda integrase (IntC3), stringently controlled by an inducible expression control sequence; transforming into the E. coli strain a bacterial plasmid comprising the DNA sequence of interest and a bacterial backbone sequence flanked by two directly repeated lambda integrase recombination sequences, wherein the bacterial backbone sequence comprises a selection marker; cultivating the transformed E. coli cells under conditions selective for the selection marker; inducing the expression of IntC3 to facilitate recombination to obtain a dimeric DNA catenane consisting of a first circular DNA molecule carrying the bacterial backbone and a second circular DNA molecule carrying the DNA sequence of interest and the phage lambda integrase recombination sequence.