title: Cell-cycle-dependent dynamics of nuclear pores: pore-free islands and lamins.
abstract: Nuclear pores are sophisticated gateways on the nuclear envelope that control macromolecular transport between the cytoplasm and nucleoplasm. So far the structural and functional aspects of nuclear pores have been extensively studied, but their distribution and density, which might reflect nuclear organization and function, remain unknown. Here, we report the cell-cycle-dependent dynamics of nuclear pores. Large distinct subdomains lacking nuclear pores are present on the nuclear surface of HeLaS3 cells in early cell-cycle stages. Such ;pore-free islands' gradually become dispersed in G1-S phase. Surprisingly, the islands are enriched with inner nuclear membrane proteins lamin A/C and emerin, but exclude lamin B. Lamin-A/C-enriched pore-free islands were also observed in human normal diploid fibroblasts and several cell lines, showing the generality of this phenomenon. Knockdown and ectopic expression analyses demonstrated that lamin A/C, but not emerin, plays an essential structural and regulatory role in the nuclear pore distribution and the formation of pore-free islands. These data thus provide strong evidence that the dynamics of nuclear pores are regulated by the reorganization of inner nuclear structures.
authors.affiliation: Cellular Dynamics Laboratory, Discovery Research Institute, RIKEN, 2-1 Hirosawa, Wako-shi, Saitama, 351-0198 Japan. maeshima@riken.jp
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Maeshima
authors.forename: Kazuhide
authors.initials: K
authors.lastname: Yahata
authors.forename: Yoko
authors.initials: Y
authors.lastname: Sasaki
authors.forename: Reiko
authors.initials: R
authors.lastname: Nakatomi
authors.forename: Taro
authors.initials: T
authors.lastname: Tachibana
authors.forename: Tsutomu
authors.initials: T
authors.lastname: Hashikawa
authors.forename: Fumio
authors.initials: F
authors.lastname: Imamoto
authors.forename: Naoko
authors.initials: N
authors.lastname: Imamoto
mesh_terms: D001859:Bone Neoplasms / Q000378:metabolism; D002453:Cell Cycle / Q000502:physiology*; D002467:Cell Nucleus / Q000648:ultrastructure; D002478:Cells, Cultured; D005347:Fibroblasts / Q000166:cytology / Q000378:metabolism; D005455:Fluorescent Antibody Technique; D006367:HeLa Cells / Q000378:metabolism; D006801:Humans; D034904:Lamin Type A / Q000235:genetics / Q000378:metabolism*; D034921:Lamin Type B / Q000235:genetics / Q000378:metabolism; D008938:Mitosis / Q000502:physiology; D009685:Nuclear Envelope; D022022:Nuclear Pore / Q000502:physiology*; D012516:Osteosarcoma / Q000378:metabolism; D010957:Plasmids
chemical_list: D034904:Lamin Type A; D034921:Lamin Type B; C440308:lamin C