Biomaterial Database

Analysis of a mycotoxin gene cluster in Aspergillus nidulans. 1995

N P Keller, and T H Adams

Department of Plant Pathology and Microbiology, Texas A&M University, College Station 77843, USA.

Aspergillus nidulans has functioned as a model system for the study of fungal genetics since the 1950s. Application of methodologies ranging from Mendelian genetics to the most sophisticated molecular biological techniques have resulted in a detailed understanding of genes and pathways involved in primary metabolism, secondary metabolism and development in A. nidulans. We have taken advantage of this background in developing A. nidulans as a genetic system to study the molecular mechanisms regulating aflatoxin biosynthesis. Aflatoxin, a carcinogenic polyketide, is the product of a lengthy biochemical pathway found in the asexual spp., A. flavus and A. parasiticus. A. nidulans possesses most if not all of this pathway and produces sterigmatocystin, the penultimate precursor of the aflatoxin pathway. We have identified a approximately 60 kb cluster of genes in A. nidulans whose products are involved in sterigmatocystin biosynthesis. This cluster contains at least 20 genes proposed to encode both enzymatic activities and regulatory proteins. Our results have shown that at least some of these genes are functionally conserved between A. nidulans, A. flavus and A. parasiticus, and that they are regulated in similar ways. Further studies of sterigmatocystin regulation in A. nidulans should yield information transferable to studies of (i) secondary metabolism in other filamentous fungi and (ii) aflatoxin regulation in A. flavus and A. parasiticus in particular.

UI	MeSH Term	Description	Entries
D008969	Molecular Sequence Data	Descriptions of specific amino acid, carbohydrate, or nucleotide sequences which have appeared in the published literature and/or are deposited in and maintained by databanks such as GENBANK, European Molecular Biology Laboratory (EMBL), National Biomedical Research Foundation (NBRF), or other sequence repositories.	Sequence Data, Molecular,Molecular Sequencing Data,Data, Molecular Sequence,Data, Molecular Sequencing,Sequencing Data, Molecular
D009183	Mycotoxins	Toxic compounds produced by FUNGI.	Fungal Toxins,Mycotoxin,Toxins, Fungal
D005810	Multigene Family	A set of genes descended by duplication and variation from some ancestral gene. Such genes may be clustered together on the same chromosome or dispersed on different chromosomes. Examples of multigene families include those that encode the hemoglobins, immunoglobulins, histocompatibility antigens, actins, tubulins, keratins, collagens, heat shock proteins, salivary glue proteins, chorion proteins, cuticle proteins, yolk proteins, and phaseolins, as well as histones, ribosomal RNA, and transfer RNA genes. The latter three are examples of reiterated genes, where hundreds of identical genes are present in a tandem array. (King & Stanfield, A Dictionary of Genetics, 4th ed)	Gene Clusters,Genes, Reiterated,Cluster, Gene,Clusters, Gene,Families, Multigene,Family, Multigene,Gene Cluster,Gene, Reiterated,Multigene Families,Reiterated Gene,Reiterated Genes
D000348	Aflatoxins	Furano-furano-benzopyrans that are produced by ASPERGILLUS from STERIGMATOCYSTIN. They are structurally related to COUMARINS and easily oxidized to an epoxide form to become ALKYLATING AGENTS. Members of the group include AFLATOXIN B1; aflatoxin B2, aflatoxin G1, aflatoxin G2; AFLATOXIN M1; and aflatoxin M2.	Aflatoxin
D000595	Amino Acid Sequence	The order of amino acids as they occur in a polypeptide chain. This is referred to as the primary structure of proteins. It is of fundamental importance in determining PROTEIN CONFORMATION.	Protein Structure, Primary,Amino Acid Sequences,Sequence, Amino Acid,Sequences, Amino Acid,Primary Protein Structure,Primary Protein Structures,Protein Structures, Primary,Structure, Primary Protein,Structures, Primary Protein
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia
D001233	Aspergillus nidulans	A species of imperfect fungi from which the antibiotic nidulin is obtained. Its teleomorph is Emericella nidulans.	Aspergillus nidulellus,Emericella nidulans
D013241	Sterigmatocystin	A carcinogenic mycotoxin produced in high yields by strains of the common molds, Aspergillus versicolor, A. nidulans, and an unidentified species of Bipolaris. It causes necrosis of the liver and kidney and has an inhibitory effect on orotic acid incorporation into nuclear RNA.
D016415	Sequence Alignment	The arrangement of two or more amino acid or base sequences from an organism or organisms in such a way as to align areas of the sequences sharing common properties. The degree of relatedness or homology between the sequences is predicted computationally or statistically based on weights assigned to the elements aligned between the sequences. This in turn can serve as a potential indicator of the genetic relatedness between the organisms.	Sequence Homology Determination,Determination, Sequence Homology,Alignment, Sequence,Alignments, Sequence,Determinations, Sequence Homology,Sequence Alignments,Sequence Homology Determinations