title: The conserved kinase NHK-1 is essential for mitotic progression and unifying acentrosomal meiotic spindles in Drosophila melanogaster.
abstract: Conventional centrosomes are absent from the spindle in female meiosis in many species, but it is not clear how multiple chromosomes form one shared bipolar spindle without centrosomes. We identified a female sterile mutant in which each bivalent chromosome often forms a separate bipolar metaphase I spindle. Unlike wild type, prophase I chromosomes fail to form a single compact structure within the oocyte nucleus, although the integrity of metaphase I chromosomes appears to be normal. Molecular analysis indicates that the mutant is defective in the conserved kinase nucleosomal histone kinase-1 (NHK-1). Isolation of further alleles and RNA interference in S2 cells demonstrated that NHK-1 is also required for mitotic progression. NHK-1 itself is phosphorylated in mitosis and female meiosis, suggesting that this kinase is part of the regulatory system coordinating progression of mitosis and meiosis.
authors.affiliation: Wellcome Trust Centre for Cell Biology, Institute of Cell Biology, School of Biological Sciences, The University of Edinburgh, Edinburgh EH9 3JR, Scotland, UK.
authors.forename: C Fiona
authors.initials: CF
authors.lastname: Cullen
authors.forename: Amy L
authors.initials: AL
authors.lastname: Brittle
authors.forename: Takashi
authors.initials: T
authors.lastname: Ito
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Ohkura
mesh_terms: D000483:Alleles; D000818:Animals; D002453:Cell Cycle; D002460:Cell Line; D002467:Cell Nucleus / Q000378:metabolism; D018385:Centrosome / Q000648:ultrastructure*; D002875:Chromosomes / Q000648:ultrastructure; D029721:Drosophila Proteins / Q000737:chemistry; D004331:Drosophila melanogaster / Q000502:physiology*; D005260:Female; D008540:Meiosis; D008938:Mitosis; D008954:Models, Biological; D008957:Models, Genetic; D009154:Mutation; D009865:Oocytes / Q000378:metabolism; D010641:Phenotype; D010766:Phosphorylation; D006656:Protamine Kinase / Q000235:genetics / Q000502:physiology*; D008941:Spindle Apparatus
chemical_list: D029721:Drosophila Proteins; C506651:Ball protein, Drosophila; D006656:Protamine Kinase