Recombinant environmental libraries provide access to microbial diversity for drug discovery from natural products.
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.
Courtois
Sophie
S
Laboratoire d'Ecologie Microbienne du Sol, UMR CNRS 5557, Université Claude Bernard Lyon 1, 69622 Villeurbanne Cedex, France.
Cappellano
Carmela M
CM
Ball
Maria
M
Francou
Francois-Xavier
FX
Normand
Philippe
P
Helynck
Gérard
G
Martinez
Asuncion
A
Kolvek
Steven J
SJ
Hopke
Joern
J
Osburne
Marcia S
MS
August
Paul R
PR
Nalin
Renaud
R
Guérineau
Michel
M
Jeannin
Pascale
P
Simonet
Pascal
P
Pernodet
Jean-Luc
JL
D000595:Amino Acid Sequence; D000900:Anti-Bacterial Agents / Q000378:metabolism*; D001419:Bacteria / Q000145:classification* / Q000235:genetics / Q000378:metabolism; D001688:Biological Products / Q000378:metabolism*; D002851:Chromatography, High Pressure Liquid; D003001:Cloning, Molecular; D003360:Cosmids; D004269:DNA, Bacterial / Q000235:genetics / Q000378:metabolism; D004926:Escherichia coli / Q000235:genetics; D015723:Gene Library; D014644:Genetic Variation; D005822:Genetic Vectors; D008969:Molecular Sequence Data; D009097:Multienzyme Complexes / Q000235:genetics; D016133:Polymerase Chain Reaction; D011995:Recombination, Genetic; D012988:Soil Microbiology; D013302:Streptomyces / Q000235:genetics; D014169:Transformation, Bacterial
D000900:Anti-Bacterial Agents; D001688:Biological Products; D004269:DNA, Bacterial; D009097:Multienzyme Complexes