Strain for the production of 6-demethyltetracycline, method for producing the strain and vector for use in the method

Abstract

Recombinant S. aureofaciens cells are provided. These cells comprise: (a) at least one CTC 11 gene; and (b) optionally (i) a CTC 09 gene; (ii) a CTC 03 gene; or (iii) a combination thereof; wherein: the CTC 11 gene is chromosomal, extra-chromosomal, or chromosomal and extra-chromosomal; the CTC 09 gene, CTC 03 gene, or a combination thereof is chromosomal, extra-chromosomal, or a combination thereof; expression of the CTC 11 gene is enhanced over that of a wild-type S. aureofaciens cell; and optionally, the CTC 09 gene, the CTC 03 gene, or both of the CTC 09 gene and the CTC 03 gene are inactivated. The present invention also contemplates vector pLP21329 and vectors for allelic replacement in a S. aureofaciens host cell. The vectors comprise: (a) a functional E. coli origin of replication; (b) a functional Streptomyces origin of replication; (c) a functional gene that imparts a positively selectable phenotype on the host cell; and ((d) a ribosomal S12 gene which is expressed in Streptomyces such that it imparts sensitivity to streptomycin to the host cell. In another embodiment, a method of mutating a target gene of a biosynthetic pathway of Streptomyces is disclosed. The method comprises (a) replacing the genomic copy of the target gene with a selectable marker gene through homologous recombination to form a first recombinant strain; and (b) replacing the selectable marker gene in the first recombinant strain with an altered copy of the target gene through homologous recombination to form a second recombinant strain.

Dependencies are inferred from the claim text.