Mutations in proteins of the Conserved Oligomeric Golgi Complex affect polarity, cell wall structure, and glycosylation in the filamentous fungus Aspergillus nidulans

S. K. Gremillion, S. D. Harris, L. Jackson-Hayes, S. G.W. Kaminskyj, D. M. Loprete, A. C. Gauthier, S. Mercer, A. J. Ravita, T. W. Hill

Research output: Contribution to journalArticlepeer-review

7 Scopus citations

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.

Original languageEnglish (US)
Pages (from-to)69-82
Number of pages14
JournalFungal Genetics and Biology
Volume73
DOIs
StatePublished - Dec 1 2014

Keywords

  • Aspergillus nidulans
  • COG complex
  • Cell wall
  • Glycosylation
  • Polarity maintenance

ASJC Scopus subject areas

  • Microbiology
  • Genetics

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