title: Cloning and characterization of novel methylsalicylic acid synthase gene involved in the biosynthesis of isoasperlactone and asperlactone in Aspergillus westerdijkiae.
abstract: Aspergillus westerdijkiae is the main producer of several biologically active polyketide metabolites including isoasperlactone and asperlactone. A 5298bp polyketide synthase gene "aomsas" has been cloned in Aspergillus westerdijkiae by using gene walking approach and RACE-PCR. The predicted amino acid sequence of aomsas shows an identity of 40-56% with different methylsalicylic acid synthase genes found in Byssochlamys nivea, P. patulum, A. terreus and Streptomyces viridochromogenes. Based on the reverse transcription PCR and kinetic secondary metabolites production studies, aomsas expression was found to be associated with the biosynthesis of isoasperlactone and asperlactone. Moreover an aomsas knockout mutant "aoDeltamsas" of A. westerdijkiae, not only lost the capacity to produce isoasperlactone and asperlactone, but also 6-methylsalicylic acid. The genetically complemented mutant ao+msas restored the biosynthesis of all the missing metabolites. Chemical complementation through the addition of 6-methylsalicylic acid, aspyrone and diepoxide to growing culture of aoDeltamsas mutant revealed that these compounds play intermediate roles in the biosynthesis of asperlactone and isoasperlactone.
authors: Université de Toulouse, Institut National Polytechnique de Toulouse, Laboratoire de Génie Chimique UMR5503 (CNRS/INPT/UPS), Ecole Nationale Supérieure Agronomique de Toulouse, Castanet Tolosan, France.
authors: Nafees
authors: N
authors: Bacha
authors: Huy Phong
authors: HP
authors: Dao
authors: Ali
authors: A
authors: Atoui
authors: Florence
authors: F
authors: Mathieu
authors: John
authors: J
authors: O'Callaghan
authors: Olivier
authors: O
authors: Puel
authors: Thierry
authors: T
authors: Liboz
authors: Alan D W
authors: AD
authors: Dobson
authors: Ahmed
authors: A
authors: Lebrihi
mesh_terms: D000217:Acyltransferases / Q000235:genetics* / Q000378:metabolism*; D000595:Amino Acid Sequence; D001230:Aspergillus / Q000201:enzymology* / Q000235:genetics; D055323:Byssochlamys / Q000201:enzymology / Q000235:genetics; D003001:Cloning, Molecular; D004271:DNA, Fungal / Q000737:chemistry / Q000235:genetics; D005656:Fungal Proteins / Q000235:genetics* / Q000378:metabolism*; D055786:Gene Knockout Techniques; D005816:Genetic Complementation Test; D008025:Ligases / Q000235:genetics* / Q000378:metabolism*; D018942:Macrolides / Q000378:metabolism*; D008969:Molecular Sequence Data; D015394:Molecular Structure; D009097:Multienzyme Complexes / Q000235:genetics* / Q000378:metabolism*; D010088:Oxidoreductases / Q000235:genetics* / Q000378:metabolism*; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid; D013302:Streptomyces / Q000201:enzymology / Q000235:genetics
chemical_list: D004271:DNA, Fungal; D005656:Fungal Proteins; D018942:Macrolides; D009097:Multienzyme Complexes; D010088:Oxidoreductases; D000217:Acyltransferases; C021587:6-methylsalicylic acid synthetase; D008025:Ligases