title: The Sec14 family glycerophospholipid-transfer protein is required for structural integrity of the spindle pole body during meiosis in fission yeast.
abstract: The fission yeast spo20+ gene encodes a glycerophospholipid-transfer protein. spo20 mutants are unable to assemble the forespore membrane properly. Here we studied the structural integrity of the spindle pole body (SPB) in spo20-H6 mutants during meiosis. Meiotic cells expressing a GFP-tagged SPB marker protein, Spo15-GFP, showed an excess number of SPBs, some of which were not localized to the spindle poles and were termed 'pseudo-SPBs'. Formation of spindles for meiosis I was significantly delayed in spo20-H6 cells, although the morphology of spindles and segregation of the sister chromatids seemed normal. The SPB of spo20-H6 contained meiosis-specific outer plaques, though outermost layers were less evident. Time-lapse studies of spo20-H6 cells showed that the pseudo-SPBs originated from normal SPBs at the spindle poles during meiosis I. Among the SPB components tested, Spo15, Spo13, Sad1 and Cut12 were localized to the pseudo-SPBs, but Sid4 was not always present. Alp4, a component of the gamma-tubulin complex, was also present in about 40% of the pseudo-SPBs. The forespore membranes initiated from both the SPBs and the pseudo-SPBs. We conclude that Spo20 plays a role in maintaining the structural integrity of the meiotic SPB, besides supplying membrane vesicles for forespore membrane assembly.
authors.affiliation: Department of Biology, Graduate School of Science, Osaka City University, Sugimoto, Sumiyoshi-ku, Osaka 558-8585, Japan.
authors.forename: Yukiko
authors.initials: Y
authors.lastname: Nakase
authors.forename: Taro
authors.initials: T
authors.lastname: Nakamura
authors.forename: Koei
authors.initials: K
authors.lastname: Okazaki
authors.forename: Aiko
authors.initials: A
authors.lastname: Hirata
authors.forename: Chikashi
authors.initials: C
authors.lastname: Shimoda
mesh_terms: D000483:Alleles; D001483:Base Sequence; D005822:Genetic Vectors; D020404:Glycerophospholipids / Q000378:metabolism; D008540:Meiosis; D008969:Molecular Sequence Data; D009154:Mutation; D049294:Phospholipid Transfer Proteins / Q000235:genetics* / Q000502:physiology*; D010957:Plasmids; D012568:Schizosaccharomyces / Q000166:cytology / Q000235:genetics / Q000648:ultrastructure*; D029702:Schizosaccharomyces pombe Proteins / Q000235:genetics* / Q000502:physiology*; D008941:Spindle Apparatus / Q000737:chemistry / Q000648:ultrastructure*
chemical_list: D020404:Glycerophospholipids; D049294:Phospholipid Transfer Proteins; D029702:Schizosaccharomyces pombe Proteins; C483440:Spo20 protein, S pombe