ORT® Background

ORT® (Operator-Repressor Titration): Cobra’s method for producing plasmid DNA without antibiotics, antibiotic resistance genes or any other selectable marker genes in Escherichia coli.

The isolation of bacterial transformants and subsequent stable plasmid maintenance has traditionally been accomplished using plasmid-borne selectable marker genes. The marker genes typically encode resistance to an antibiotic such as ampicillin, or alternatively encode an essential gene that complements a host cell deficiency (auxotrophy).

The disadvantages of these systems are:
  • Requirement of plasmid-borne gene transcription
  • Imposition of a metabolic burden on the host
  • Reduction in the yield of the recombinant protein
  • Increased costs and downstream processing requirements as a result of the use of antibiotics in large scale fermentation
  • Increasing regulatory compliance

More about Antibiotic-free Maintenance System (ORT® & X-mark™)...

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