title: Mutations in proteins of the Conserved Oligomeric Golgi Complex affect polarity, cell wall structure, and glycosylation in the filamentous fungus Aspergillus nidulans.
abstract: We have described two Aspergillus nidulans gene mutations, designated podB1 (polarity defective) and swoP1 (swollen cell), which cause temperature-sensitive defects during polarization. Mutant strains also displayed unevenness and abnormal thickness of cell walls. Un-polarized or poorly-polarized mutant cells were capable of establishing normal polarity after a shift to a permissive temperature, and mutant hyphae shifted from permissive to restrictive temperature show wall and polarity abnormalities in subsequent growth. The mutated genes (podB=AN8226.3; swoP=AN7462.3) were identified as homologues of COG2 and COG4, respectively, each predicted to encode a subunit of the multi-protein COG (Conserved Oligomeric Golgi) Complex involved in retrograde vesicle trafficking in the Golgi apparatus. Down-regulation of COG2 or COG4 resulted in abnormal polarization and cell wall staining. The GFP-tagged COG2 and COG4 homologues displayed punctate, Golgi-like localization. Lectin-blotting indicated that protein glycosylation was altered in the mutant strains compared to the wild type. A multicopy expression experiment showed evidence for functional interactions between the homologues COG2 and COG4 as well as between COG2 and COG3. To date, this work is the first regarding a functional role of the COG proteins in the development of a filamentous fungus.
authors.affiliation: Department of Biology, Armstrong State University, 11935 Abercorn Street, Savannah, GA 31419, USA. Electronic address: Sara.Gremillion@armstrong.edu.
authors.forename: S K
authors.initials: SK
authors.lastname: Gremillion
authors.affiliation: Center for Plant Science Innovation, University of Nebraska, Lincoln, NE 68588-0660, USA.
authors.forename: S D
authors.initials: SD
authors.lastname: Harris
authors.affiliation: Department of Chemistry, Rhodes College, 2000 North Parkway, Memphis, TN 38112, USA.
authors.forename: L
authors.initials: L
authors.lastname: Jackson-Hayes
authors.affiliation: Department of Biology, University of Saskatchewan, 112 Science Place Saskatoon, Saskatchewan S7N 5E2, Canada.
authors.forename: S G W
authors.initials: SG
authors.lastname: Kaminskyj
authors.affiliation: Department of Chemistry, Rhodes College, 2000 North Parkway, Memphis, TN 38112, USA.
authors.forename: D M
authors.initials: DM
authors.lastname: Loprete
authors.affiliation: Department of Biology, Armstrong State University, 11935 Abercorn Street, Savannah, GA 31419, USA.
authors.forename: A C
authors.initials: AC
authors.lastname: Gauthier
authors.affiliation: Department of Biology, Rhodes College, 2000 North Parkway, Memphis, TN 38112, USA.
authors.forename: S
authors.initials: S
authors.lastname: Mercer
authors.affiliation: Department of Biology, Armstrong State University, 11935 Abercorn Street, Savannah, GA 31419, USA.
authors.forename: A J
authors.initials: AJ
authors.lastname: Ravita
authors.affiliation: Department of Biology, Rhodes College, 2000 North Parkway, Memphis, TN 38112, USA.
authors.forename: T W
authors.initials: TW
authors.lastname: Hill
mesh_terms: D000595:Amino Acid Sequence; D001233:Aspergillus nidulans / Q000235:genetics* / Q000378:metabolism; D016764:Cell Polarity / Q000235:genetics*; D002473:Cell Wall / Q000235:genetics / Q000648:ultrastructure; D005656:Fungal Proteins / Q000235:genetics* / Q000378:metabolism; D006031:Glycosylation; D006056:Golgi Apparatus / Q000378:metabolism*; D026901:Membrane Transport Proteins / Q000235:genetics; D008969:Molecular Sequence Data; D009154:Mutation; D012441:Saccharomyces cerevisiae / Q000235:genetics; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics; D033921:Vesicular Transport Proteins / Q000235:genetics
chemical_list: C112749:COG2 protein, S cerevisiae; C468122:COG4 protein, S cerevisiae; D005656:Fungal Proteins; D026901:Membrane Transport Proteins; D029701:Saccharomyces cerevisiae Proteins; D033921:Vesicular Transport Proteins
keywords: Aspergillus nidulans; COG complex; Cell wall; Glycosylation; Polarity maintenance