Chemical induction of silent biosynthetic pathway transcription in Aspergillus niger

J Ind Microbiol Biotechnol. 2009 Sep;36(9):1199-213. doi: 10.1007/s10295-009-0601-4. Epub 2009 Jun 12.

Abstract

Manipulation of the fungal epigenome is hypothesized to be an effective method for accessing natural products from silent biosynthetic pathways. A library of epigenetic modifiers was tested using the fungus Aspergillus niger to determine the impact of small-molecule inhibitors on reversing the transcriptional suppression of biosynthetic genes involved in polyketide (PKS), non-ribosomal peptide (NRPS), and hybrid PKS-NRPS (HPN) production. Examination of expressed sequence tag libraries from A. niger demonstrated that >70% of its PKS-, NRPS-, and HPN-encoding gene clusters were transcriptionally suppressed under standard laboratory culture conditions. Using a chemical epigenetic methodology, we showed that treatment of A. niger with suberoylanilide hydroxamic acid and 5-azacytidine led to the transcriptional upregulation of many secondary-metabolite-encoding biosynthetic gene clusters. Chemical epigenetic modifiers exhibited positional biases for upregulating chromosomally distal gene clusters. In addition, a phylogenetic-based preference was noted in the upregulation of reducing clade I PKS gene clusters, while reducing clade IV PKS gene clusters were largely unaffected. Manipulating epigenetic features in fungi is a powerful method for accessing the products of silent biosynthetic pathways. Moreover, this approach can be readily incorporated into modern microbial screening operations.

Publication types

  • Evaluation Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aspergillus niger / drug effects*
  • Aspergillus niger / enzymology*
  • Aspergillus niger / genetics
  • Aspergillus niger / growth & development
  • Azacitidine / pharmacology*
  • Biological Products / biosynthesis
  • Biological Products / genetics
  • Biosynthetic Pathways / drug effects*
  • Biotechnology / methods*
  • Epigenesis, Genetic
  • Expressed Sequence Tags
  • Fungal Proteins / genetics
  • Fungal Proteins / metabolism*
  • Gene Expression Regulation, Fungal*
  • Gene Library
  • Hydroxamic Acids / pharmacology*
  • Multigene Family*
  • Peptide Synthases / genetics
  • Peptide Synthases / metabolism
  • Polyketide Synthases / genetics
  • Polyketide Synthases / metabolism
  • Reverse Transcriptase Polymerase Chain Reaction
  • Up-Regulation
  • Vorinostat

Substances

  • Biological Products
  • Fungal Proteins
  • Hydroxamic Acids
  • Vorinostat
  • Polyketide Synthases
  • Peptide Synthases
  • non-ribosomal peptide synthase
  • Azacitidine