Recombinant Environmental Libraries Provide Access to Microbial Diversity for Drug Discovery from Natural Products |
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| Authors: | Sophie Courtois Carmela M Cappellano Maria Ball Francois-Xavier Francou Philippe Normand Grard Helynck Asuncion Martinez Steven J Kolvek Joern Hopke Marcia S Osburne Paul R August Renaud Nalin Michel Gurineau Pascale Jeannin Pascal Simonet and Jean-Luc Pernodet |
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| Affiliation: | Sophie Courtois, Carmela M. Cappellano, Maria Ball, Francois-Xavier Francou, Philippe Normand, Gérard Helynck, Asuncion Martinez, Steven J. Kolvek, Joern Hopke, Marcia S. Osburne, Paul R. August, Renaud Nalin, Michel Guérineau, Pascale Jeannin, Pascal Simonet, and Jean-Luc Pernodet |
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| Abstract: | To further explore possible avenues for accessing microbial biodiversity for drug discovery from natural products, we constructed and screened a 5,000-clone “shotgun” environmental DNA library by using an Escherichia coli-Streptomyces lividans shuttle cosmid vector and DNA inserts from microbes derived directly (without cultivation) from soil. The library was analyzed by several means to assess diversity, genetic content, and expression of heterologous genes in both expression hosts. We found that the phylogenetic content of the DNA library was extremely diverse, representing mostly microorganisms that have not been described previously. The library was screened by PCR for sequences similar to parts of type I polyketide synthase genes and tested for the expression of new molecules by screening of live colonies and cell extracts. The results revealed new polyketide synthase genes in at least eight clones. In addition, at least five additional clones were confirmed by high-pressure liquid chromatography analysis and/or biological activity to produce heterologous molecules. These data reinforce the idea that exploiting previously unknown or uncultivated microorganisms for the discovery of novel natural products has potential value and, most importantly, suggest a strategy for developing this technology into a realistic and effective drug discovery tool. |
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