Chromatin-independent nuclear envelope assembly induced by Ran GTPase in Xenopus egg extracts.
The nuclear envelope (NE) forms a controlled boundary between the cytoplasm and the nucleus of eukaryotic cells. To facilitate investigation of mechanisms controlling NE assembly, we developed a cell-free system made from Xenopus laevis eggs to study the process in the absence of chromatin. NEs incorporating nuclear pores were assembled around beads coated with the guanosine triphosphatase Ran, forming pseudo-nuclei that actively imported nuclear proteins. NE assembly required the cycling of guanine nucleotides on Ran and was promoted by RCC1, a nucleotide exchange factor recruited to beads by Ran-guanosine diphosphate (Ran-GDP). Thus, concentration of Ran-GDP followed by generation of Ran-GTP is sufficient to induce NE assembly.
Zhang
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Biomedical Research Centre, University of Dundee, Level 5, Ninewells Hospital and Medical School, Dundee DD1 9SY, Scotland, UK. c.zhang@icrf.icnet.uk
Clarke
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D000818:Animals; D001693:Biological Transport, Active; D018797:Cell Cycle Proteins; D002457:Cell Extracts; D002843:Chromatin / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000378:metabolism; D020662:Guanine Nucleotide Exchange Factors; D006153:Guanosine Diphosphate / Q000378:metabolism; D006160:Guanosine Triphosphate / Q000378:metabolism; D007381:Intermediate Filament Proteins; D034921:Lamin Type B; D008561:Membrane Fusion; D009685:Nuclear Envelope / Q000378:metabolism* / Q000648:ultrastructure; D009687:Nuclear Proteins / Q000378:metabolism; D056489:Nucleoplasmins; D010063:Ovum; D010750:Phosphoproteins / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D013692:Telophase; D029867:Xenopus Proteins; D014982:Xenopus laevis; D020931:ran GTP-Binding Protein / Q000378:metabolism*
D018797:Cell Cycle Proteins; D002457:Cell Extracts; D002843:Chromatin; D004268:DNA-Binding Proteins; D020662:Guanine Nucleotide Exchange Factors; D007381:Intermediate Filament Proteins; D034921:Lamin Type B; D009687:Nuclear Proteins; D056489:Nucleoplasmins; D010750:Phosphoproteins; C499304:RCC1 protein, Xenopus; D011993:Recombinant Fusion Proteins; D029867:Xenopus Proteins; D006153:Guanosine Diphosphate; D006160:Guanosine Triphosphate; D020931:ran GTP-Binding Protein