title: Chromosomal association of Ran during meiotic and mitotic divisions.
abstract: Recent studies in Xenopus egg extracts indicate that the small G protein Ran has a central role in spindle assembly and nuclear envelope reformation. We determined Ran localization and dynamics in cells during M phase. By immunofluorescence, Ran is accumulated on the chromosomes of meiosis-II-arrested Xenopus eggs. In living cells, fluorescently labeled Ran associated with the chromosomes in Xenopus and remained associated during anaphase when eggs were artificially activated. Fluorescent Ran associated with chromosomes in mouse eggs, during meiotic maturation and early embryonic divisions in starfish, and to a lesser degree during mitosis of a cultured mammalian cell line. Chromosomal Ran undergoes constant flux. From photobleach experiments in immature starfish oocytes, chromosomal Ran has a k(off) of approximately 0.06 second(-1), and binding analysis suggests that there is a single major site. The chromosomal interactions may serve to keep Ran-GTP in the vicinity of the chromosomes for spindle assembly and nuclear envelope reformation.
authors.affiliation: Department of Physiology, University of Connecticut Health Center, Farmington, CT 06032, USA.
authors.forename: Beth
authors.initials: B
authors.lastname: Hinkle
authors.forename: Boris
authors.initials: B
authors.lastname: Slepchenko
authors.forename: Melissa M
authors.initials: MM
authors.lastname: Rolls
authors.forename: Tobias C
authors.initials: TC
authors.lastname: Walther
authors.forename: Pascal A
authors.initials: PA
authors.lastname: Stein
authors.forename: Lisa M
authors.initials: LM
authors.lastname: Mehlmann
authors.forename: Jan
authors.initials: J
authors.lastname: Ellenberg
authors.forename: Mark
authors.initials: M
authors.lastname: Terasaki
mesh_terms: D000818:Animals; D002478:Cells, Cultured; D002875:Chromosomes / Q000378:metabolism*; D033481:Chromosomes, Mammalian / Q000378:metabolism; D007700:Kinetics; D008540:Meiosis; D051379:Mice; D008938:Mitosis; D009865:Oocytes / Q000166:cytology / Q000378:metabolism; D011485:Protein Binding; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D014982:Xenopus laevis; D020931:ran GTP-Binding Protein / Q000235:genetics / Q000378:metabolism*
chemical_list: D012333:RNA, Messenger; D020931:ran GTP-Binding Protein