The conserved kinase NHK-1 is essential for mitotic progression and unifying acentrosomal meiotic spindles in Drosophila melanogaster.
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.
Cullen
C Fiona
CF
Wellcome Trust Centre for Cell Biology, Institute of Cell Biology, School of Biological Sciences, The University of Edinburgh, Edinburgh EH9 3JR, Scotland, UK.
Brittle
Amy L
AL
Ito
Takashi
T
Ohkura
Hiroyuki
H
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
D029721:Drosophila Proteins; C506651:Ball protein, Drosophila; D006656:Protamine Kinase