title: Expression profiling of non-aflatoxigenic Aspergillus parasiticus mutants obtained by 5-azacytosine treatment or serial mycelial transfer.
abstract: Aflatoxins are carcinogenic secondary metabolites produced by the fungi Aspergillus flavus and Aspergillus parasiticus. Previous studies found that repeated serial mycelial transfer or treatment of A. parasiticus with 5-azacytidine produced colonies with a fluffy phenotype and inability to produce aflatoxins. To understand how these treatments affect expression of genes involved in aflatoxin production and development, we carried out expressed sequence tag (EST)-based microarray assays to identify genes in treated clones that are differentially expressed compared to the wild-type. Expression of 183 genes was significantly dysregulated. Of these, 38 had at least two-fold or lower expression compared to the untreated control and only two had two-fold or higher expression. The most frequent change was downregulation of genes predicted to encode membrane-bound proteins. Based on this result we hypothesize that the treatments cause changes in the structure of cellular and organelle membranes that prevent normal development and aflatoxin biosynthesis.
authors: Southern Regional Research Center, ARS/USDA, 1100 Robert E. Lee Blvd., New Orleans, LA, USA. jrw@juno.com
authors: Jeffrey R
authors: JR
authors: Wilkinson
authors: Shubha P
authors: SP
authors: Kale
authors: Deepak
authors: D
authors: Bhatnagar
authors: Jiujiang
authors: J
authors: Yu
authors: Kenneth C
authors: KC
authors: Ehrlich
mesh_terms: D000348:Aflatoxins / Q000096:biosynthesis*; D001230:Aspergillus / Q000235:genetics* / Q000378:metabolism; D003001:Cloning, Molecular; D003596:Cytosine / Q000031:analogs & derivatives / Q000494:pharmacology; D015536:Down-Regulation; D020224:Expressed Sequence Tags; D020869:Gene Expression Profiling; D015966:Gene Expression Regulation, Fungal; D005810:Multigene Family; D020411:Oligonucleotide Array Sequence Analysis; D010641:Phenotype; D014158:Transcription, Genetic
chemical_list: D000348:Aflatoxins; C039854:5-azacytosine; D003596:Cytosine