The Caenorhabditis elegans kinetochore reorganizes at prometaphase and in response to checkpoint stimuli.
Previous studies of the kinetochore in mammalian systems have demonstrated that this structure undergoes reorganizations after microtubule attachment or in response to activation of the spindle checkpoint. Here, we show that the Caenorhabditis elegans kinetochore displays analogous rearrangements at prometaphase, when microtubule/chromosome interactions are being established, and after exposure to checkpoint stimuli such as nocodazole or anoxia. These reorganizations are characterized by a dissociation of several kinetochore proteins, including HCP-1/CeCENP-F, HIM-10/CeNuf2, SAN-1/CeMad3, and CeBUB-1, from the centromere. We further demonstrate that at metaphase, despite having dissociated from the centromere, these reorganized kinetochore proteins maintain their associations with the metaphase plate. After checkpoint activation, these proteins are detectable as large "flares" that project out laterally from the metaphase plate. Disrupting these gene products via RNA interference results in sensitivity to checkpoint stimuli, as well as defects in the organization of chromosomes at metaphase. These phenotypes suggest that these proteins, and by extension their reorganization during mitosis, are important for mediating the checkpoint response as well as directing the assembly of the metaphase plate.
Stear
Jeffrey H
JH
Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA.
Roth
Mark B
MB
D000818:Animals; D017173:Caenorhabditis elegans / Q000648:ultrastructure*; D029742:Caenorhabditis elegans Proteins / Q000378:metabolism; D002453:Cell Cycle; D018797:Cell Cycle Proteins / Q000096:biosynthesis; D002503:Centromere / Q000648:ultrastructure; D002868:Chromosomal Proteins, Non-Histone / Q000096:biosynthesis / Q000378:metabolism; D006657:Histones / Q000378:metabolism; D000860:Hypoxia; D018386:Kinetochores / Q000378:metabolism*; D008677:Metaphase; D008840:Microfilament Proteins; D008853:Microscopy; D008870:Microtubules / Q000648:ultrastructure; D008938:Mitosis; D015739:Nocodazole / Q000494:pharmacology; D010641:Phenotype; D049468:Prometaphase; D011418:Prophase; D011494:Protein Kinases / Q000096:biosynthesis; D017346:Protein Serine-Threonine Kinases; D034622:RNA Interference; D008941:Spindle Apparatus
D029742:Caenorhabditis elegans Proteins; D018797:Cell Cycle Proteins; D002868:Chromosomal Proteins, Non-Histone; D006657:Histones; D008840:Microfilament Proteins; C490197:NUF2 protein, human; C094772:centromere protein F; C400272:hcp-1 protein, C elegans; D011494:Protein Kinases; C090464:Bub1 spindle checkpoint protein; D017346:Protein Serine-Threonine Kinases; D015739:Nocodazole