The Chromokinesin, KLP3A, Drives Mitotic Spindle Pole Separation during Prometaphase and Anaphase and Facilitates Chromatid Motility

Mijung Kwon, Sandra Morales-Mulia, Ingrid Brust-Mascher, Gregory C. Rogers, David J. Sharp, Jonathan M. Scholey

Research output: Contribution to journalArticle

53 Scopus citations

Abstract

Mitosis requires the concerted activities of multiple microtubule (MT)-based motor proteins. Here we examined the contribution of the chromokinesin, KLP3A, to mitotic spindle morphogenesis and chromosome movements in Drosophila embryos and cultured S2 cells. By immunofluorescence, KLP3A associates with nonfibrous punctae that concentrate in nuclei and display MT-dependent associations with spindles. These punctae concentrate in indistinct domains associated with chromosomes and central spindles and form distinct bands associated with telophase midbodies. The functional disruption of KLP3A by antibodies or dominant negative proteins in embryos, or by RNA interference (RNAi) in S2 cells, does not block mitosis but produces defects in mitotic spindles. Time-lapse confocal observations of mitosis in living embryos reveal that KLP3A inhibition disrupts the organization of interpolar (ip) MTs and produces short spindles. Kinetic analysis suggests that KLP3A contributes to spindle pole separation during the prometaphase-to-metaphase transition (when it antagonizes Ncd) and anaphase B, to normal rates of chromatid motility during anaphase A, and to the proper spacing of daughter nuclei during telophase. We propose that KLP3A acts on MTs associated with chromosome arms and the central spindle to organize ipMT bundles, to drive spindle pole separation and to facilitate chromatid motility.

Original languageEnglish (US)
Pages (from-to)219-233
Number of pages15
JournalMolecular Biology of the Cell
Volume15
Issue number1
DOIs
StatePublished - Jan 2004

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ASJC Scopus subject areas

  • Molecular Biology
  • Genetics
  • Cell Biology

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