HCP-4/CENP-C promotes the prophase timing of centromere resolution by enabling the centromere association of HCP-6 in Caenorhabditis elegans.
Prior to microtubule capture, sister centromeres resolve from one another, coming to rest on opposite surfaces of the condensing chromosome. Subsequent assembly of sister kinetochores at each sister centromere generates a geometry favorable for equal levels of segregation of chromatids. The holocentric chromosomes of Caenorhabditis elegans are uniquely suited for the study of centromere resolution and subsequent kinetochore assembly. In C. elegans, only two proteins have been identified as being necessary for centromere resolution, the kinase AIR-2 (prophase only) and the centromere protein HCP-4/CENP-C. Here we found that the loss of proteins involved in chromosome cohesion bypassed the requirement for HCP-4/CENP-C but not for AIR-2. Interestingly, the loss of cohesin proteins also restored the localization of HCP-6 to the kinetochore. The loss of the condensin II protein HCP-6 or MIX-1/SMC2 impaired centromere resolution. Furthermore, the loss of HCP-6 or MIX-1/SMC2 resulted in no centromere resolution when either nocodazole or RNA interference (RNAi) of the kinetochore protein KNL-1 perturbed spindle-kinetochore interactions. This result suggests that normal prophase centromere resolution is mediated by condensin II proteins, which are actively recruited to sister centromeres to mediate the process of resolution.
Moore
Landon L
LL
Department of Genetics and Genomics, Boston University School of Medicine, 715 Albany St., E642, Boston, MA 02118, USA. lmoore@bu.edu
Stanvitch
Gerald
G
Roth
Mark B
MB
Rosen
David
D
D000251:Adenosine Triphosphatases / Q000378:metabolism; D000818:Animals; D017173:Caenorhabditis elegans / Q000166:cytology* / Q000196:embryology / Q000235:genetics / Q000378:metabolism*; D029742:Caenorhabditis elegans Proteins / Q000235:genetics / Q000378:metabolism*; D018797:Cell Cycle Proteins / Q000235:genetics / Q000378:metabolism*; D002503:Centromere / Q000378:metabolism*; D002842:Chromatids / Q000378:metabolism; D002868:Chromosomal Proteins, Non-Histone / Q000235:genetics / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000378:metabolism; D004625:Embryo, Nonmammalian; D008938:Mitosis; D046912:Multiprotein Complexes; D011418:Prophase; D011485:Protein Binding; D021381:Protein Transport; D034622:RNA Interference
D029742:Caenorhabditis elegans Proteins; D018797:Cell Cycle Proteins; D002868:Chromosomal Proteins, Non-Histone; D004268:DNA-Binding Proteins; C430464:HCP-4 protein, C elegans; C459882:HCP-6 protein, C elegans; C110487:MIX-1 protein, C elegans; D046912:Multiprotein Complexes; C108312:condensin complexes; D000251:Adenosine Triphosphatases