title: The bZIP transcription factor MeaB mediates nitrogen metabolite repression at specific loci.
abstract: In Fusarium fujikuroi, bikaverin (BIK) biosynthesis is subject to repression by nitrogen. Unlike most genes subject to nitrogen metabolite repression, it has been shown that transcription of bik biosynthetic genes is not AreA dependent. Searching for additional transcription factors that may be involved in nitrogen regulation, we cloned and characterized the orthologue of Aspergillus nidulans meaB, which encodes a bZIP transcription factor. Two transcripts are derived from F. fujikuroi meaB: the large transcript (meaB(L)) predominates under nitrogen-sufficient conditions and the smaller transcript (meaB(S)) under nitrogen limitation, in an AreA-dependent manner. MeaB is specifically translocated to the nucleus under nitrogen-sufficient conditions in both F. fujikuroi and A. nidulans. Deletion of meaB resulted in partial upregulation of several nitrogen-regulated genes, but only in the ΔmeaB ΔareA double mutant were the bikaverin genes significantly upregulated in the presence of glutamine. These data demonstrate that MeaB and AreA coordinately mediate nitrogen metabolite repression and, importantly, that independently of AreA, MeaB can mediate nitrogen metabolite repression at specific loci in F. fujikuroi.
authors: Institut für Botanik der Westfälischen Wilhelms-Universität Münster, Germany.
authors: Dominik
authors: D
authors: Wagner
authors: Anne
authors: A
authors: Schmeinck
authors: Magdalena
authors: M
authors: Mos
authors: Igor Y
authors: IY
authors: Morozov
authors: Mark X
authors: MX
authors: Caddick
authors: Bettina
authors: B
authors: Tudzynski
mesh_terms: D001233:Aspergillus nidulans / Q000235:genetics / Q000378:metabolism; D050976:Basic-Leucine Zipper Transcription Factors / Q000235:genetics / Q000378:metabolism*; D003001:Cloning, Molecular; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism; D005670:Fusarium / Q000235:genetics / Q000378:metabolism*; D017353:Gene Deletion; D015966:Gene Expression Regulation, Fungal; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D009584:Nitrogen / Q000378:metabolism* / Q000494:pharmacology; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism; D044004:Xanthones / Q000378:metabolism
chemical_list: D050976:Basic-Leucine Zipper Transcription Factors; D005656:Fungal Proteins; C100491:MeaB protein, Emericella nidulans; D011993:Recombinant Fusion Proteins; D014157:Transcription Factors; D044004:Xanthones; D049452:Green Fluorescent Proteins; C000269:bikaverin; D009584:Nitrogen