title: The Aspergillus nidulans F-box protein GrrA links SCF activity to meiosis.
abstract: Cellular differentiation relies on precise and controlled means of gene expression that act on several levels to ensure a flexible and defined spatio-temporal expression of a given gene product. In our aim to identify transcripts enriched during fruiting body formation of the homothallic ascomycete Aspergillus (Emericella) nidulans, the grrA gene could be identified in a negative subtraction hybridization screening procedure. It encodes a protein similar to fungal F-box proteins, which function as substrate receptors for ubiquitin ligases, and that is highly related to the Saccharomyces cerevisiae regulatory protein Grr1p. Expression studies confirmed induction of grrA transcription and expression of its gene product during cleistothecial development of A. nidulans. Functional complementation of a yeast grr1Delta mutant was achieved by overexpression of the grrA coding sequence. A grrADelta deletion mutant resembles the wild-type in hyphal growth, asexual sporulation, Hülle cell formation or development of asci-containing cleistothecia, but is unable to produce mature ascospores due to a block in meiosis as demonstrated by cytological staining of cleistothecial contents. Our results specify a particular involvement of the E3 ubiquitin ligase SCFGrrA in meiosis and sexual spore formation of an ascomyceteous fungus and shed light on the diverse functions of ubiquitin-proteasome-mediated protein degradation in eukaryotic development.
authors.affiliation: Institute of Microbiology and Genetics, Department of Molecular Microbiology and Genetics, Georg-August-University Göttingen, Germany.
authors.forename: Sven
authors.initials: S
authors.lastname: Krappmann
authors.forename: Nadja
authors.initials: N
authors.lastname: Jung
authors.forename: Branka
authors.initials: B
authors.lastname: Medic
authors.forename: Silke
authors.initials: S
authors.lastname: Busch
authors.forename: Rolf A
authors.initials: RA
authors.lastname: Prade
authors.forename: Gerhard H
authors.initials: GH
authors.lastname: Braus
mesh_terms: D000595:Amino Acid Sequence; D001233:Aspergillus nidulans / Q000235:genetics* / Q000378:metabolism / Q000502:physiology; D001483:Base Sequence; D015152:Blotting, Northern; D044783:F-Box Proteins / Q000235:genetics* / Q000378:metabolism / Q000502:physiology; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology; D017353:Gene Deletion; D018507:Gene Expression Regulation, Developmental; D015966:Gene Expression Regulation, Fungal; D008540:Meiosis / Q000235:genetics* / Q000502:physiology; D008969:Molecular Sequence Data; D044843:SKP Cullin F-Box Protein Ligases / Q000235:genetics / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D013172:Spores, Fungal / Q000254:growth & development / Q000378:metabolism; D044767:Ubiquitin-Protein Ligases / Q000378:metabolism
chemical_list: D044783:F-Box Proteins; D005656:Fungal Proteins; D029701:Saccharomyces cerevisiae Proteins; D044843:SKP Cullin F-Box Protein Ligases; D044767:Ubiquitin-Protein Ligases