Abstract
The Nup84p complex consists of five nucleoporins (Nup84p, Nup85p, Nup120p, Nup145p-C, and Seh1p) and Sec13p, a bona fide subunit of the COPII coat complex. We show that a pool of green fluorescent protein-tagged Sec13p localizes to the nuclear pores in vivo, and identify sec13 mutant alleles that are synthetically lethal with nup85Delta and affect the localization of a green fluorescent protein-Nup49p reporter protein. In the electron microscope, sec13 mutants exhibit structural defects in nuclear pore complex (NPC) and nuclear envelope organization. For the assembly of the complex, Nup85p, Nup120p, and Nup145p-C are essential. A highly purified Nup84p complex was isolated from yeast under native conditions and its molecular mass was determined to be 375 kD by quantitative scanning transmission electron microscopy and analytical ultracentrifugation, consistent with a monomeric complex. Furthermore, the Nup84p complex exhibits a Y-shaped, triskelion-like morphology 25 nm in diameter in the transmission electron microscope. Thus, the Nup84p complex constitutes a paradigm of an NPC structural module with distinct composition, structure, and a role in nuclear mRNA export and NPC bio- genesis.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Alleles
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Amino Acid Sequence
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Cell Nucleus / chemistry
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Cell Nucleus / metabolism
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Cell Nucleus / ultrastructure
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Chromatography, Gel
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Epistasis, Genetic
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Fungal Proteins / genetics
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Fungal Proteins / isolation & purification
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Fungal Proteins / metabolism*
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Fungal Proteins / ultrastructure
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Genes, Lethal / genetics
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Membrane Proteins / genetics
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Membrane Proteins / isolation & purification
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Membrane Proteins / metabolism*
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Membrane Proteins / ultrastructure
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Microscopy, Electron, Scanning Transmission
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Molecular Sequence Data
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Molecular Weight
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Mutation / genetics
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Nuclear Envelope / chemistry*
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Nuclear Envelope / metabolism
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Nuclear Envelope / ultrastructure
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Nuclear Pore Complex Proteins*
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Nuclear Proteins / genetics
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Nuclear Proteins / isolation & purification
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Nuclear Proteins / metabolism*
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Nuclear Proteins / ultrastructure*
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Porins / genetics
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Porins / isolation & purification
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Porins / metabolism
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Porins / ultrastructure
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Protein Binding
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RNA-Binding Proteins / genetics
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RNA-Binding Proteins / isolation & purification
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RNA-Binding Proteins / metabolism
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RNA-Binding Proteins / ultrastructure
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Recombinant Fusion Proteins / genetics
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Recombinant Fusion Proteins / isolation & purification
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Recombinant Fusion Proteins / metabolism
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Recombinant Fusion Proteins / ultrastructure
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Saccharomyces cerevisiae / chemistry*
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Saccharomyces cerevisiae / cytology
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Saccharomyces cerevisiae / genetics
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Saccharomyces cerevisiae Proteins*
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Temperature
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Ultracentrifugation
Substances
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Fungal Proteins
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Membrane Proteins
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NUP120 protein, S cerevisiae
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NUP145 protein, S cerevisiae
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NUP84 protein, S cerevisiae
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NUP85 protein, S cerevisiae
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Nuclear Pore Complex Proteins
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Nuclear Proteins
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Porins
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RNA-Binding Proteins
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Recombinant Fusion Proteins
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SEC13 protein, S cerevisiae
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Saccharomyces cerevisiae Proteins