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dc.contributor.authorGoldberg, Martin W*
dc.contributor.authorWiese, C*
dc.contributor.authorAllen, Terence D*
dc.contributor.authorWilson, Katherine L*
dc.date.accessioned2010-04-01T13:59:31Z
dc.date.available2010-04-01T13:59:31Z
dc.date.issued1997-02
dc.identifier.citationDimples, pores, star-rings, and thin rings on growing nuclear envelopes: evidence for structural intermediates in nuclear pore complex assembly. 1997, 110 ( Pt 4):409-20 J. Cell. Sci.en
dc.identifier.issn0021-9533
dc.identifier.pmid9067593
dc.identifier.urihttp://hdl.handle.net/10541/95499
dc.description.abstractWe used field emission in-lens scanning electron microscopy to examine newly-assembled, growing nuclear envelopes in Xenopus egg extracts. Scattered among nuclear pore complexes were rare 'dimples' (outer membrane depressions, 5-35 nm diameter), more abundant holes (pores) with a variety of edge geometries (35-45 nm diameter; 3.3% of structures), pores containing one to eight triangular 'star-ring' subunits (2.1% of total), and more complicated structures. Neither mature complexes, nor these novel structures, formed when wheat germ agglutinin (which binds O-glycosylated nucleoporins) was added at high concentrations (>500 microg/ml) directly to the assembly reaction; low concentrations (10 microg/ml) had no effect. However at intermediate concentrations (50-100 microg/ml), wheat germ agglutinin caused a dramatic, sugar-reversible accumulation of 'empty' pores, and other structures; this effect correlated with the lectin-induced precipitation of a variable proportion of each major Xenopus wheat-germ-agglutinin-binding nucleoporin. Another inhibitor, dibromo-BAPTA (5,5'-dibromo-1,2-bis[o-aminophenoxylethane-N,N,N',N'-tetraacetic acid), had different effects depending on its time of addition to the assembly reaction. When 1 mM dibromo-BAPTA was added at time zero, no pore-related structures formed. However, when dibromo-BAPTA was added to growing nuclei 40-45 minutes after initiating assembly, star-rings and other structures accumulated, suggesting that dibromo-BAPTA can inhibit multiple stages in pore complex assembly. We propose that assembly begins with the formation and stabilization of a hole (pore) through the nuclear envelope, and that dimples, pores, star-rings, and thin rings are structural intermediates in nuclear pore complex assembly.
dc.language.isoenen
dc.subject.meshAnimals
dc.subject.meshCell Division
dc.subject.meshCell Membrane
dc.subject.meshCytoplasm
dc.subject.meshCytoskeleton
dc.subject.meshEgtazic Acid
dc.subject.meshNuclear Envelope
dc.subject.meshWheat Germ Agglutinins
dc.subject.meshXenopus
dc.titleDimples, pores, star-rings, and thin rings on growing nuclear envelopes: evidence for structural intermediates in nuclear pore complex assembly.en
dc.typeArticleen
dc.contributor.departmentCRC Department of Structural Cell Biology, Paterson Institute for Cancer Research, Christie Hospital National Health Service Trust, Manchester, UK.en
dc.identifier.journalJournal of Cell Scienceen
html.description.abstractWe used field emission in-lens scanning electron microscopy to examine newly-assembled, growing nuclear envelopes in Xenopus egg extracts. Scattered among nuclear pore complexes were rare 'dimples' (outer membrane depressions, 5-35 nm diameter), more abundant holes (pores) with a variety of edge geometries (35-45 nm diameter; 3.3% of structures), pores containing one to eight triangular 'star-ring' subunits (2.1% of total), and more complicated structures. Neither mature complexes, nor these novel structures, formed when wheat germ agglutinin (which binds O-glycosylated nucleoporins) was added at high concentrations (>500 microg/ml) directly to the assembly reaction; low concentrations (10 microg/ml) had no effect. However at intermediate concentrations (50-100 microg/ml), wheat germ agglutinin caused a dramatic, sugar-reversible accumulation of 'empty' pores, and other structures; this effect correlated with the lectin-induced precipitation of a variable proportion of each major Xenopus wheat-germ-agglutinin-binding nucleoporin. Another inhibitor, dibromo-BAPTA (5,5'-dibromo-1,2-bis[o-aminophenoxylethane-N,N,N',N'-tetraacetic acid), had different effects depending on its time of addition to the assembly reaction. When 1 mM dibromo-BAPTA was added at time zero, no pore-related structures formed. However, when dibromo-BAPTA was added to growing nuclei 40-45 minutes after initiating assembly, star-rings and other structures accumulated, suggesting that dibromo-BAPTA can inhibit multiple stages in pore complex assembly. We propose that assembly begins with the formation and stabilization of a hole (pore) through the nuclear envelope, and that dimples, pores, star-rings, and thin rings are structural intermediates in nuclear pore complex assembly.


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