LITTLE NUCLEI genes affecting nuclear morphology in Arabidopsis thaliana

Plant Cell. 2007 Sep;19(9):2793-803. doi: 10.1105/tpc.107.053231. Epub 2007 Sep 14.

Abstract

Efforts to understand nuclear organization in plant cells have received little assistance from the better-studied animal nuclei, because plant proteomes do not contain recognizable counterparts to the key animal proteins involved in nuclear organization, such as lamin nuclear intermediate filament proteins. Previous studies identified a plant-specific insoluble nuclear protein in carrot (Daucus carota), called Nuclear Matrix Constituent Protein1 (NMCP1), which contains extensive coiled-coil domains and localizes to the nuclear periphery. Here, we describe a genetic characterization of two NMCP1-related nuclear proteins in Arabidopsis thaliana, LITTLE NUCLEI1 (LINC1) and LINC2. Disruption of either gene caused a reduction in nuclear size and altered nuclear morphology. Moreover, combining linc1 and linc2 mutations had an additive effect on nuclear size and morphology but a synergistic effect on chromocenter number (reduction) and whole-plant morphology (dwarfing). The reduction in nuclear size in the linc1 linc2 double mutant was not accompanied by a corresponding change in endopolyploidy. Rather, the density of DNA packaging at all endopolyploid levels in the linc1 linc2 mutants was increased significantly. Our results indicate that the LINC coiled-coil proteins are important determinants of plant nuclear structure.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Arabidopsis / cytology*
  • Arabidopsis / genetics
  • Arabidopsis Proteins / chemistry
  • Arabidopsis Proteins / genetics*
  • Cell Nucleus / metabolism*
  • Cell Size
  • DNA, Plant / metabolism
  • Genes, Plant
  • Molecular Sequence Data
  • Mutation / genetics
  • Nuclear Proteins / chemistry
  • Nuclear Proteins / genetics*
  • Nuclear Proteins / metabolism
  • Phenotype
  • Plant Proteins / metabolism
  • Polyploidy
  • Protein Transport

Substances

  • Arabidopsis Proteins
  • At1g13220 protein, Arabidopsis
  • At1g67230 protein, Arabidopsis
  • DNA, Plant
  • NMCP1 protein, Daucus carota
  • Nuclear Proteins
  • Plant Proteins