A gel-less isolation of untagged plasmid DNA insert from vector backbone in homogeneous format

Agarose gel electrophoresis with subsequent DNA extraction from gel is routinely used for DNA fragment isolation after plasmid DNA digestion. We describe a gel-less method for DNA fragment isolation after plasmid DNA digestion which is based on in-solution negative selection through depletion of vector backbone bearing LoxP sites by sorption on solid phase-immobilized mutated Cre recombinase. The method might be especially useful in preparation of DNA fragments for transgenic animal generation where residual agarose presence is a concern, and DNA fragments are frequently large in size and thus might be mechanically damaged during purification with conventional affinity-based gel extraction methods.