1. Academic Validation
  2. Subcloning and expression of midecamycin polyketide synthase genes from Streptomyces mycarofaciens 1748

Subcloning and expression of midecamycin polyketide synthase genes from Streptomyces mycarofaciens 1748

  • Chin J Biotechnol. 1991;7(4):241-51.
X Zhu 1 Y Wang L Jin X Xu
Affiliations

Affiliation

  • 1 Institute of Medicinal Biotechnology, Chinese Academy of Medical Science, Beijing.
PMID: 1824237
Abstract

A 2.4 kb fragment containing the midecamycin polyketide synthase genes (mps) was subcloned from the preliminary clone pCN8B12 out of the genomic library of midecamycin-producing strain S. mycarofaciens 1748, by using the homologous DNA of the actinorhodin polyketide synthase gene (act I) as hybridization probe. This DNA fragment was subcloned onto Streptomyces/E. coli shuttle vector pMHM3. A recombinant plasmid pCG2 was obtained. The transformation of the polyketide synthase deficient mutant of actinorhodin-producing strain, S. colicolor TK17, with pCG2 DNA resulted in the production of an Antibacterial compound which was similar neither to actinorhodin nor to midecamycin. The transformation of spiramycin-producing strain S. ambofaciens with pCG2 DNA increased spiramycin production in the fermentation broth. The transformation of the regulatory mutant of daunorubicin-producing strain with pCG2 DNA resulted in the production of epsilon-rhodomycinone verified by TLC and HPLC analyses. The pCG2 DNA also could be functionally expressed in tetracenomycin C-producing strain S. glaucescens. However, it could not be expressed in the blocked mutants of erythromycin-producing strain Saccharopolyspora erythrarea WMH 15,261. These suggest that the pCG2 DNA may complement polyketide synthase gene deficiency or have some regulatory function in certain polyketide antibiotic-producing strains.

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