BigPatents India

A prokaryotic recombinant host cellcomprising a heterologous replication initiation protein that activates a condiÂtional origin of replication and an extrachromosomal DNA molecule comprising a heterologous therapeutic gene and a conditional origin of replication whose functionality in the prokaryolic recombinant host cell requires a replicadon initiating protein which is foreign to the host cell is described. The host cell may comprise a pir gene having at least one mutation, which may occur in the pir gene copy number control region, the pir gene leucine zipper-like motif, or the pir gene DNA binding region.