| 摘要 |
The present invention is directed to integration vectors including food-grade integration vectors, a method of increasing the stability of the inheritance of genes in microorganisms and transformed microorganisms containing an integrated vector and which exhibit an increase in the stability of inheritance of a gene. The integration vector is comprised of a first DNA sequence encoding a temperature sensitive plasmid maintenance and replication region, a second DNA sequence encoding at least one selectable marker gene, a third DNA sequence encoding an insertion sequence, and a fourth DNA sequence which encodes an unstable gene. The method of increasing the stability of the inheritance of a gene includes introducing the integration vector into a host microorganism, selecting transformed microorganisms, and confirming that selected microorganisms exhibit an increase in the stability of inheritance of a gene encoding a trait. Transformed microorganisms are provided which have at least one integration vector integrated into the genome and which exhibit an increase in the stability of the inheritance of a gene encoding a trait. The invention also provides DNA sequences substantially corresponding to a temperature sensitive plasmid maintenance and replication sequence, a nisin resistance gene, and a novel lactococcal insertion sequence.
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