title: A basic-region helix-loop-helix protein-encoding gene (devR) involved in the development of Aspergillus nidulans.
abstract: Basic-region helix-loop-helix (bHLH) proteins form an interesting class of eukaryotic transcription factors often involved in developmental processes. Here, a so far unknown bHLH protein-encoding gene of the filamentous ascomycete Aspergillus nidulans was isolated and designated devR for regulator of development. Deletion of devR revealed that the gene is non-essential for vegetative growth. However, the deletion mutant produced wrinkled colonies, a yellow pigment and did not form conidia on minimal agar plates. Conidiophore development was initiated normally, and colonies produced conidiophores with metulae and phialides. However, the phialides continued to grow filamentously and produced a second conidiophore with a vesicle at its end. The addition of KCl (0.6 M) to the medium suppressed the knock-out phenotype. The DeltadevR phenotype resembled that of a mutation in the tcsA gene encoding a histidine kinase domain and a response regulator domain. Here, we generated a tcsA deletion mutant. In a DeltatcsA strain, a DevR-Egfp protein fusion was detected in the cytoplasm, whereas in the wild type, the protein fusion was exclusively located in the nuclei, indicating that TcsA is required for nuclear localization of DevR. devR mRNA steady-state levels were similar in sporulating and vegetatively growing mycelia, and independent of a functional brlA gene. Moreover, under all conditions tested, self-crossing of the DeltadevR mutant strain was never observed. Taken together, devR encodes a bHLH regulatory protein that is part of the tcsA signal transduction network and required for development under standard growth conditions.
authors.affiliation: Institut für Mikrobiologie, Universität Hannover, Schneiderberg 50, D-30167 Hannover, Germany.
authors.forename: André
authors.initials: A
authors.lastname: Tüncher
authors.forename: Hans
authors.initials: H
authors.lastname: Reinke
authors.forename: Goran
authors.initials: G
authors.lastname: Martic
authors.forename: Maria Louise
authors.initials: ML
authors.lastname: Caruso
authors.forename: Axel A
authors.initials: AA
authors.lastname: Brakhage
mesh_terms: D000595:Amino Acid Sequence; D001233:Aspergillus nidulans / Q000166:cytology / Q000235:genetics* / Q000254:growth & development* / Q000378:metabolism; D002467:Cell Nucleus; D003001:Cloning, Molecular; D003470:Culture Media / Q000737:chemistry; D003593:Cytoplasm; D004271:DNA, Fungal / Q000737:chemistry / Q000302:isolation & purification; D005656:Fungal Proteins / Q000737:chemistry / Q000235:genetics* / Q000502:physiology*; D017353:Gene Deletion; D005800:Genes, Fungal; D017930:Genes, Reporter; D049452:Green Fluorescent Proteins; D018257:Helix-Loop-Helix Motifs; D008164:Luminescent Proteins / Q000235:genetics / Q000378:metabolism; D008969:Molecular Sequence Data; D010860:Pigments, Biological / Q000096:biosynthesis; D011189:Potassium Chloride / Q000378:metabolism; D011494:Protein Kinases / Q000235:genetics / Q000502:physiology; D021381:Protein Transport; D012333:RNA, Messenger / Q000032:analysis; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA; D015398:Signal Transduction; D014157:Transcription Factors / Q000235:genetics / Q000502:physiology
chemical_list: D003470:Culture Media; D004271:DNA, Fungal; D005656:Fungal Proteins; D008164:Luminescent Proteins; D010860:Pigments, Biological; D012333:RNA, Messenger; D014157:Transcription Factors; D049452:Green Fluorescent Proteins; D011189:Potassium Chloride; D011494:Protein Kinases; C415590:TcsA protein, Aspergillus nidulans