Chemical induction of silent biosynthetic pathway transcription in Aspergillus niger.
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.
Fisch
K M
KM
School of Chemistry, University of Bristol, Cantocks Close, Bristol BS8 1TS, UK.
Gillaspy
A F
AF
Gipson
M
M
Henrikson
J C
JC
Hoover
A R
AR
Jackson
L
L
Najar
F Z
FZ
Wägele
H
H
Cichewicz
R H
RH
D001234:Aspergillus niger / Q000187:drug effects* / Q000201:enzymology* / Q000235:genetics / Q000254:growth & development; D001374:Azacitidine / Q000494:pharmacology*; D001688:Biological Products / Q000096:biosynthesis / Q000235:genetics; D053898:Biosynthetic Pathways / Q000187:drug effects*; D001709:Biotechnology / Q000379:methods*; D044127:Epigenesis, Genetic; D020224:Expressed Sequence Tags; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism*; D015966:Gene Expression Regulation, Fungal; D015723:Gene Library; D006877:Hydroxamic Acids / Q000494:pharmacology*; D005810:Multigene Family; D010453:Peptide Synthases / Q000235:genetics / Q000378:metabolism; D048630:Polyketide Synthases / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015854:Up-Regulation; D000077337:Vorinostat
D001688:Biological Products; D005656:Fungal Proteins; D006877:Hydroxamic Acids; D000077337:Vorinostat; D048630:Polyketide Synthases; D010453:Peptide Synthases; C104385:non-ribosomal peptide synthase; D001374:Azacitidine