title: Mitotic chromosome length scales in response to both cell and nuclear size.
abstract: Multicellular development requires that cells reduce in size as a result of consecutive cell divisions without increase in embryo volume. To maintain cellular integrity, organelle size adapts to cell size throughout development. During mitosis, the longest chromosome arm must be shorter than half of the mitotic spindle for proper chromosome segregation. Using high-resolution time-lapse microscopy of living Caenorhabditis elegans embryos, we have quantified the relation between cell size and chromosome length. In control embryos, chromosome length scaled to cell size. Artificial reduction of cell size resulted in a shortening of chromosome length, following a trend predicted by measurements from control embryos. Disturbing the RAN (Ras-related nuclear protein)-GTP gradient decoupled nuclear size from cell size and resulted in chromosome scaling to nuclear size rather than cell size; smaller nuclei contained shorter chromosomes independent of cell size. In sum, quantitative analysis relating cell, nuclear, and chromosome size predicts two levels of chromosome length regulation: one through cell size and a second in response to nuclear size.
authors.affiliation: Department of Biology, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599.
authors.forename: Anne-Marie
authors.initials: AM
authors.lastname: Ladouceur
authors.affiliation: Institute for Research in Immunology and Cancer (IRIC), Faculty of Medicine, University of Montreal, Montreal, Quebec H3T 1J4, Canada.
authors.forename: Jonas F
authors.initials: JF
authors.lastname: Dorn
authors.affiliation: Department of Biology, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599 pmaddox@unc.edu.
authors.forename: Paul S
authors.initials: PS
authors.lastname: Maddox
mesh_terms: D000818:Animals; D017173:Caenorhabditis elegans / Q000166:cytology / Q000196:embryology*; D029742:Caenorhabditis elegans Proteins / Q000378:metabolism; D002467:Cell Nucleus / Q000378:metabolism*; D002875:Chromosomes / Q000378:metabolism*; D004625:Embryo, Nonmammalian / Q000166:cytology / Q000196:embryology*; D006801:Humans; D008938:Mitosis / Q000502:physiology*; D020931:ran GTP-Binding Protein / Q000378:metabolism
chemical_list: D029742:Caenorhabditis elegans Proteins; D020931:ran GTP-Binding Protein