title: Molecular genetic analysis of vesicular transport in Aspergillus niger reveals partial conservation of the molecular mechanism of exocytosis in fungi.
abstract: The filamentous fungus Aspergillus niger is an industrially exploited protein expression platform, well known for its capacity to secrete high levels of proteins. To study the process of protein secretion in A. niger, we established a GFP-v-SNARE reporter strain in which the trafficking and dynamics of secretory vesicles can be followed in vivo. The biological role of putative A. niger orthologues of seven secretion-specific genes, known to function in key aspects of the protein secretion machinery in Saccharomyces cerevisiae, was analysed by constructing respective gene deletion mutants in the GFP-v-SNARE reporter strain. Comparison of the deletion phenotype of conserved proteins functioning in the secretory pathway revealed common features but also interesting differences between S. cerevisiae and A. niger. Deletion of the S. cerevisiae Sec2p orthologue in A. niger (SecB), encoding a guanine exchange factor for the GTPase Sec4p (SrgA in A. niger), did not have an obvious phenotype, while SEC2 deletion in S. cerevisiae is lethal. Similarly, deletion of the A. niger orthologue of the S. cerevisiae exocyst subunit Sec3p (SecC) did not result in a lethal phenotype as in S. cerevisiae, although severe growth reduction of A. niger was observed. Deletion of secA, secH and ssoA (encoding SecA, SecH and SsoA the A. niger orthologues of S. cerevisiae Sec1p, Sec8p and Sso1/2p, respectively) showed that these genes are essential for A. niger, similar to the situation in S. cerevisiae. These data demonstrate that the orchestration of exocyst-mediated vesicle transport is only partially conserved in S. cerevisiae and A. niger.
authors.affiliation: Kluyver Centre for Genomics of Industrial Fermentation, P.O. Box 5057, 2600 GA Delft, The Netherlands.|Department Molecular Microbiology and Biotechnology, Institute of Biology Leiden, Leiden University, Sylviusweg 72, 2333 BE Leiden, The Netherlands.
authors.forename: Min Jin
authors.initials: MJ
authors.lastname: Kwon
authors.affiliation: Department Molecular Microbiology and Biotechnology, Institute of Biology Leiden, Leiden University, Sylviusweg 72, 2333 BE Leiden, The Netherlands.
authors.forename: Mark
authors.initials: M
authors.lastname: Arentshorst
authors.affiliation: Department Applied and Molecular Microbiology, Institute of Biotechnology, Berlin University of Technology, Gustav-Meyer-Allee 25, 13355 Berlin, Germany.
authors.forename: Markus
authors.initials: M
authors.lastname: Fiedler
authors.affiliation: Department Molecular Microbiology and Biotechnology, Institute of Biology Leiden, Leiden University, Sylviusweg 72, 2333 BE Leiden, The Netherlands.
authors.forename: Florence L M
authors.initials: FLM
authors.lastname: de Groen
authors.affiliation: Department Molecular Microbiology and Biotechnology, Institute of Biology Leiden, Leiden University, Sylviusweg 72, 2333 BE Leiden, The Netherlands.
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Punt
authors.affiliation: Department Applied and Molecular Microbiology, Institute of Biotechnology, Berlin University of Technology, Gustav-Meyer-Allee 25, 13355 Berlin, Germany.|Kluyver Centre for Genomics of Industrial Fermentation, P.O. Box 5057, 2600 GA Delft, The Netherlands.|Department Molecular Microbiology and Biotechnology, Institute of Biology Leiden, Leiden University, Sylviusweg 72, 2333 BE Leiden, The Netherlands.
authors.forename: Vera
authors.initials: V
authors.lastname: Meyer
authors.affiliation: Kluyver Centre for Genomics of Industrial Fermentation, P.O. Box 5057, 2600 GA Delft, The Netherlands.|Department Molecular Microbiology and Biotechnology, Institute of Biology Leiden, Leiden University, Sylviusweg 72, 2333 BE Leiden, The Netherlands.
authors.forename: Arthur F J
authors.initials: AFJ
authors.lastname: Ram
mesh_terms: D001234:Aspergillus niger / Q000235:genetics* / Q000378:metabolism*; D005089:Exocytosis; D005656:Fungal Proteins / Q000378:metabolism*; D017353:Gene Deletion; D020043:Genes, Essential; D005800:Genes, Fungal; D017930:Genes, Reporter; D049452:Green Fluorescent Proteins / Q000032:analysis / Q000235:genetics; D050296:Microbial Viability; D021381:Protein Transport; D011993:Recombinant Fusion Proteins / Q000032:analysis / Q000235:genetics; D050600:SNARE Proteins / Q000235:genetics; D022161:Transport Vesicles / Q000235:genetics*
chemical_list: D005656:Fungal Proteins; D011993:Recombinant Fusion Proteins; D050600:SNARE Proteins; D049452:Green Fluorescent Proteins