Abstract
For proper chromosome segregation, the sister kinetochores must attach to microtubules extending from the opposite spindle poles. Any errors in microtubule attachment can induce aneuploidy. In this study, we identify a novel conserved Caenorhabditis elegans microtubule-associated protein, regulator of microtubule dynamics 1 (RMD-1), that localizes to spindle microtubules and spindle poles. Depletion of RMD-1 induces severe defects in chromosome segregation, probably through merotelic attachments between microtubules and chromosomes. Although rmd-1 embryos also have a mild defect in microtubule growth, we find that mutants of the microtubule growth regulator XMAP215/ZYG-9 show much weaker segregation defects. This suggests that the microtubule growth defect in rmd-1 embryos does not cause abnormal chromosome segregation. We also see that RMD-1 interacts with aurora B in vitro. Our results suggest that RMD-1 functions in chromosome segregation in C. elegans embryos, possibly through the aurora B-mediated pathway. Human homologues of RMD-1 could also bind microtubules, which would suggest a function for these proteins in chromosome segregation during mitosis in other organisms as well.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Amino Acid Sequence
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Animals
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Aurora Kinase B
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Aurora Kinases
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Caenorhabditis elegans / embryology
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Caenorhabditis elegans / genetics*
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Caenorhabditis elegans / ultrastructure
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Caenorhabditis elegans Proteins / chemistry
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Caenorhabditis elegans Proteins / genetics
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Caenorhabditis elegans Proteins / metabolism
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Caenorhabditis elegans Proteins / physiology*
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Chromosome Segregation / physiology*
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Embryo, Nonmammalian / metabolism
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Embryo, Nonmammalian / ultrastructure
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Humans
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Kinetochores / metabolism
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Mice
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Microtubule-Associated Proteins / chemistry
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Microtubule-Associated Proteins / genetics
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Microtubule-Associated Proteins / physiology*
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Microtubules / metabolism
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Microtubules / ultrastructure
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Molecular Sequence Data
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Protein Serine-Threonine Kinases / metabolism
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Protein Structure, Tertiary
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Sequence Alignment
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Spindle Apparatus / metabolism
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Spindle Apparatus / ultrastructure
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Xenopus laevis
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Zebrafish / metabolism
Substances
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Caenorhabditis elegans Proteins
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Microtubule-Associated Proteins
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Rmd-1 protein, C elegans
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ZYG-9 protein, C elegans
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AURKB protein, human
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Aurkb protein, mouse
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Aurora Kinase B
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Aurora Kinases
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Protein Serine-Threonine Kinases
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air-2 protein, C elegans