The conserved kinase SRPK regulates karyosome formation and spindle microtubule assembly in Drosophila oocytes

Benjamin Loh, Fiona Cullen, Nina Vogt, Hiroyuki Ohkura

Research output: Contribution to journalArticlepeer-review

Abstract

In Drosophila oocytes, after the completion of recombination, meiotic chromosomes form a compact cluster called the karyosome within the nucleus, and later assemble spindle microtubules without centrosomes. Although these oocyte specific phenomena are also observed in humans, their molecular basis is not well understood. Here we report essential roles for the conserved kinase SRPK in both karyosome formation and spindle microtubule assembly in oocytes. We have identified a female sterile srpk mutant through a cytological screen for karyosome defects. Unlike most karyosome mutants, the karyosome defect is independent of the meiotic recombination checkpoint. Heterochromatin clustering found within the wild-type karyosome is disrupted in the mutant. Strikingly, a loss of SRPK severely prevents microtubule assembly for acentrosomal spindles in mature oocytes. Subsequently, bi-orientation and segregation of meiotic chromosomes are also defective. Therefore, this study demonstrates new roles of this conserved kinase in two independent meiotic steps specific to oocytes.
Original languageEnglish
Pages (from-to)4457-4462
JournalJournal of Cell Science
Volume125
Issue number19
DOIs
Publication statusPublished - Oct 2012

Keywords

  • Drosophila
  • SRPK
  • Kinase
  • Meiosis
  • Mitosis
  • Oocyte
  • Spindle

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