title: Intranuclear DNA density affects chromosome condensation in metazoans.
abstract: Chromosome condensation is critical for accurate inheritance of genetic information. The degree of condensation, which is reflected in the size of the condensed chromosomes during mitosis, is not constant. It is differentially regulated in embryonic and somatic cells. In addition to the developmentally programmed regulation of chromosome condensation, there may be adaptive regulation based on spatial parameters such as genomic length or cell size. We propose that chromosome condensation is affected by a spatial parameter called the chromosome amount per nuclear space, or "intranuclear DNA density." Using Caenorhabditis elegans embryos, we show that condensed chromosome sizes vary during early embryogenesis. Of importance, changing DNA content to haploid or polyploid changes the condensed chromosome size, even at the same developmental stage. Condensed chromosome size correlates with interphase nuclear size. Finally, a reduction in nuclear size in a cell-free system from Xenopus laevis eggs resulted in reduced condensed chromosome sizes. These data support the hypothesis that intranuclear DNA density regulates chromosome condensation. This suggests an adaptive mode of chromosome condensation regulation in metazoans.
authors.affiliation: Cell Architecture Laboratory, Structural Biology Center, National Institute of Genetics, Yata 1111, Mishima, Shizuoka 411-8540, Japan.
authors.forename: Yuki
authors.initials: Y
authors.lastname: Hara
authors.forename: Mari
authors.initials: M
authors.lastname: Iwabuchi
authors.forename: Keita
authors.initials: K
authors.lastname: Ohsumi
authors.forename: Akatsuki
authors.initials: A
authors.lastname: Kimura
mesh_terms: D000818:Animals; D017173:Caenorhabditis elegans; D029742:Caenorhabditis elegans Proteins / Q000235:genetics / Q000378:metabolism; D002467:Cell Nucleus / Q000378:metabolism*; D053145:Cell Nucleus Size; D048429:Cell Size; D002474:Cell-Free System / Q000378:metabolism; D002875:Chromosomes / Q000235:genetics / Q000378:metabolism; D042003:DNA Packaging; D018509:DNA, Helminth / Q000235:genetics; D004625:Embryo, Nonmammalian / Q000166:cytology / Q000378:metabolism; D047108:Embryonic Development; D005260:Female; D009690:Nucleic Acid Conformation; D011003:Ploidies; D014982:Xenopus laevis
chemical_list: D029742:Caenorhabditis elegans Proteins; D018509:DNA, Helminth