Patent ID: 6808896
Filing Date: 2004-10-26
Classification: C12N

Abstract:
A method for producing a protein, comprising:(a) culturing a bacterial host cell comprising at least two copies of the gene encoding the protein stably integrated into the chromosome in different positions, wherein at least one DNA construct is integrated into a non-functional conditionally essential chromosomal gene(s) of the bacterial host, wherein the DNA construct comprises: (i) a non-functional copy of the conditionally essential gene(s); and (ii) at least one copy of the gene encoding the protein located between the non-functional copy and a DNA fragment homologous to a DNA sequence located adjacent to the non-functional conditionally essential gene(s) of the chromosome; wherein a first recombination between the non-functional conditionally essential gene and the non-functional copy results in a functional conditionally essential gene(s) located on the chromosome, and wherein the bacterial host cell had a copy of the gene of interest in the chromosome prior to integration of the at least one DNA construct; and(b) recovering the protein.