Actin-and protien-4.1-containing filaments link nuclear pore complexes to subnuclear organelles in Xenopus oocyte nuclei

Elena Kiseleva, Sheona P. Drummond, Martin W. Goldberg, Sandra A. Rutherford, Terence D. Allen, Katherine L. Wilson

Research output: Contribution to journalArticlepeer-review

Abstract

We imaged the interiors of relatively intact Xenopus oocyte nuclei by field emission scanning electron microscopy (feSEM) and visualized a network of filaments that attach to nuclear pore complexes and extend throughout the nucleus. Within the nucleus, these 'pore-linked filaments' (PLFs) were embedded into spherical structures 100 nm to ∼ 5 μm in diameter. A subset of spheres was identified as Cajal bodies by immuno-gold labeling; the rest were inferred to be nucleoli and snurposomes both of which are abundant in Xenopus oocyte nuclei. Most PLFs were independent of chromatin. The thickness of a typical PLF was 40 nm (range, ∼12-100 nm), including the 4 nm chromium coat. PLFs located inside the nucleus merged, bundled and forked, suggesting architectural adaptability. The PLF network collapsed upon treatment with latrunculin A, which depolymerizes actin filaments. Jasplakinolide, which stabilizes actin filaments, produced PLFs with more open substructure including individual filaments with evenly-spaced rows of radially projecting short filaments. Immuno-gold labeling of untreated oocyte nuclei showed that actin and protein 4.1 each localized on PLFs. Protein 4.1-gold epitopes were spaced at ∼120 nm intervals along filaments, and were often paired (∼70 nm apart) at filament junctions. We suggest that protein 4.1 and actin contribute to the structure of a network of heterogeneous filaments that link nuclear pore complexes to subnuclear organelles, and discuss possible functions for PLFs in nuclear assembly and intranuclear traffic.

Original languageEnglish (US)
Pages (from-to)2481-2490
Number of pages10
JournalJournal of cell science
Volume117
Issue number12
DOIs
StatePublished - May 15 2004

Keywords

  • Actin
  • Cajal bodies
  • Nuclear matrix
  • Nuclear pore complex
  • Nucleocytoplasmic transport
  • Nucleous
  • Protien 4.1

ASJC Scopus subject areas

  • Cell Biology

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