title: Brr6 drives the Schizosaccharomyces pombe spindle pole body nuclear envelope insertion/extrusion cycle.
abstract: The fission yeast interphase spindle pole body (SPB) is a bipartite structure in which a bulky cytoplasmic domain is separated from a nuclear component by the nuclear envelope. During mitosis, the SPB is incorporated into a fenestra that forms within the envelope during mitotic commitment. Closure of this fenestra during anaphase B/mitotic exit returns the cytoplasmic component to the cytoplasmic face of an intact interphase nuclear envelope. Here we show that Brr6 is transiently recruited to SPBs at both SPB insertion and extrusion. Brr6 is required for both SPB insertion and nuclear envelope integrity during anaphase B/mitotic exit. Genetic interactions with apq12 and defective sterol assimilation suggest that Brr6 may alter envelope composition at SPBs to promote SPB insertion and extrusion. The restriction of the Brr6 domain to eukaryotes that use a polar fenestra in an otherwise closed mitosis suggests a conserved role in fenestration to enable a single microtubule organizing center to nucleate both cytoplasmic and nuclear microtubules on opposing sides of the nuclear envelope.
authors: Cancer Research UK Cell Division Group, Paterson Institute for Cancer Research, Manchester M20 4BX, England, UK.
authors: Tiina
authors: T
authors: Tamm
authors: Agnes
authors: A
authors: Grallert
authors: Emily P S
authors: EP
authors: Grossman
authors: Isabel
authors: I
authors: Alvarez-Tabares
authors: Frances E
authors: FE
authors: Stevens
authors: Iain M
authors: IM
authors: Hagan
mesh_terms: D002467:Cell Nucleus / Q000378:metabolism; D003593:Cytoplasm / Q000378:metabolism; D005455:Fluorescent Antibody Technique; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D008938:Mitosis; D009685:Nuclear Envelope / Q000378:metabolism*; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism*; D012568:Schizosaccharomyces / Q000378:metabolism* / Q000648:ultrastructure; D029702:Schizosaccharomyces pombe Proteins / Q000235:genetics / Q000378:metabolism*; D008941:Spindle Apparatus / Q000378:metabolism*
chemical_list: C569203:Brr6 protein, S pombe; D008565:Membrane Proteins; D009687:Nuclear Proteins; D029702:Schizosaccharomyces pombe Proteins