Tandem repeats in precursor protein stabilize transcript levels and production levels of the fungal ribosomally synthesized and post-translationally modified peptide ustiloxin B.

Ustiloxin B is a ribosomally synthesized and post-translationally modified peptide (RiPP) first reported in Ascomycetes. Its biosynthetic pathway was recently identified in the filamentous fungus Aspergillus flavus. The precursor protein of ustiloxin B, UstA, has a signal peptide to the endoplasmic reticulum at its N-terminal and a subsequent tandemly highly repeated segment cleaved at Lys-Arg dipeptides by Kex2 protease; such proteins are called Kex2-processed repeat proteins (KEPs).

Ustiloxin biosynthetic machinery is not compatible between Aspergillus flavus and Ustilaginoidea virens.

Ustiloxins are ribosomally synthesized and post-translationally modified peptides (RiPPs) first reported in Ascomycetes. Originally identified as metabolites of the rice pathogenic fungus Ustilaginoidea virens, they were recently identified among the metabolites of the mold Aspergillus flavus, along with their corresponding biosynthetic gene cluster. Ustilaginoidea virens produces ustiloxins A and B, whereas A.

Promoter tools for further development of as a platform for fungal secondary metabolite production.

Background: The filamentous fungus is widely used for secondary metabolite production by heterologous expression; thus, a wide variety of promoter tools is necessary to broaden the application of this species. Here we built a procedure to survey genes constitutively highly expressed in 83 transcriptome datasets obtained under various conditions affecting secondary metabolite production, to find promoters useful for heterologous expression of genes in .

Results: To test the ability of the promoters of the top 6 genes to induce production of a fungal secondary metabolite, ustiloxin B, we inserted the promoters before the start codon of , which encodes the transcription factor of the gene cluster responsible for ustiloxin B biosynthesis, in .

Phylogenetic relationships and natural hybridization in rabbitfishes (Teleostei: Siganidae) inferred from mitochondrial and nuclear DNA analyses.

Phylogenetic relationships of rabbitfishes (the family Siganidae), ecologically important components as primary consumers in coral reef communities, were studied using mitochondrial cytochrome b gene and nuclear ITS1 (internal transcribed spacer 1) sequence analyses. The analyses of 19 out of 22 species known in the Western Pacific region revealed that siganids are genetically clustered into three major clades, which are characterized by some morphological and ecological traits. Between closely related species, such as Siganus guttatus-S.