Regulation of chamber-specific gene expression in the developing heart by Irx4

Science. 1999 Feb 19;283(5405):1161-4. doi: 10.1126/science.283.5405.1161.


The vertebrate heart consists of two types of chambers, the atria and the ventricles, which differ in their contractile and electrophysiological properties. Little is known of the molecular mechanisms by which these chambers are specified during embryogenesis. Here a chicken iroquois-related homeobox gene, Irx4, was identified that has a ventricle-restricted expression pattern at all stages of heart development. Irx4 protein was shown to regulate the chamber-specific expression of myosin isoforms by activating the expression of the ventricle myosin heavy chain-1 (VMHC1) and suppressing the expression of the atrial myosin heavy chain-1 (AMHC1) in the ventricles. Thus, Irx4 may play a critical role in establishing chamber-specific gene expression in the developing heart.

Publication types

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

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Atrial Myosins*
  • Avian Proteins*
  • Chick Embryo
  • Gene Expression Regulation, Developmental*
  • Heart Atria / embryology*
  • Heart Atria / metabolism
  • Heart Atria / virology
  • Heart Ventricles / embryology*
  • Heart Ventricles / metabolism
  • Heart Ventricles / virology
  • Homeodomain Proteins / chemistry
  • Homeodomain Proteins / genetics
  • Homeodomain Proteins / physiology*
  • In Situ Hybridization
  • Molecular Sequence Data
  • Muscle Proteins / genetics*
  • Myosin Heavy Chains / genetics
  • Myosins / genetics*
  • Phenotype
  • Recombinant Fusion Proteins
  • Retroviridae / genetics
  • Retroviridae / physiology


  • Avian Proteins
  • Homeodomain Proteins
  • Irx4 protein, Gallus gallus
  • Muscle Proteins
  • Recombinant Fusion Proteins
  • VMHC1 protein, Gallus gallus
  • Atrial Myosins
  • AMHC1 protein, chicken
  • Myosin Heavy Chains
  • Myosins

Associated data

  • GENBANK/AF091504