MIX-1: an essential component of the C. elegans mitotic machinery executes X chromosome dosage compensation

Cell. 1998 Jan 23;92(2):265-77. doi: 10.1016/s0092-8674(00)80920-4.


We show that a functional component of the C. elegans mitotic machinery regulates X chromosome gene expression. This protein, MIX-1, is a member of the dosage compensation complex that associates specifically with hermaphrodite X chromosomes to reduce their gene expression during interphase. MIX-1 also associates with all mitotic chromosomes to ensure their proper segregation. Both dosage compensation and mitosis are severely disrupted by mix-1 mutations. MIX-1 belongs to the SMC protein family required for mitotic chromosome condensation and segregation in yeast and frogs. Thus, an essential, conserved component of mitotic chromosomes has been recruited to the dosage compensation process. Rather than dosage compensation and mitosis being achieved by two separate sets of related genes, these two processes share an identical component, indicating a common mechanism for establishing higher order chromosome structure and proper X chromosome gene expression.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Caenorhabditis elegans / embryology
  • Caenorhabditis elegans / genetics*
  • Caenorhabditis elegans Proteins*
  • Cell Cycle Proteins / analysis
  • Cell Cycle Proteins / chemistry
  • Cell Cycle Proteins / genetics*
  • Disorders of Sex Development
  • Dosage Compensation, Genetic*
  • Female
  • Genes, Helminth / genetics*
  • Helminth Proteins / analysis
  • Helminth Proteins / chemistry
  • Helminth Proteins / genetics*
  • Interphase
  • Male
  • Mitosis / genetics*
  • Models, Genetic
  • Molecular Sequence Data
  • Molecular Weight
  • Mutation
  • Sequence Homology, Amino Acid
  • X Chromosome / chemistry


  • Caenorhabditis elegans Proteins
  • Cell Cycle Proteins
  • Helminth Proteins
  • MIX-1 protein, C elegans

Associated data

  • GENBANK/U96387