Pitx2 regulates cardiac left-right asymmetry by patterning second cardiac lineage-derived myocardium

Dev Biol. 2006 Aug 15;296(2):437-49. doi: 10.1016/j.ydbio.2006.06.009. Epub 2006 Jun 14.

Abstract

Current models of left-right asymmetry hold that an early asymmetric signal is generated at the node and transduced to lateral plate mesoderm in a linear signal transduction cascade through the function of the Nodal signaling molecule. The Pitx2 homeobox gene functions at the final stages of this cascade to direct asymmetric morphogenesis of selected organs including the heart. We previously showed that Pitx2 regulated an asymmetric pathway that was independent of cardiac looping suggesting a second asymmetric cardiac pathway. It has been proposed that in the cardiac outflow tract Pitx2 functions in both cardiac neural crest, as a target of canonical Wnt-signaling, and in the mesoderm-derived cardiac second lineage. We used fate mapping, conditional loss of function, and chimera analysis in mice to investigate the role of Pitx2 in outflow tract morphogenesis. Our findings reveal that Pitx2 is dispensable in the cardiac neural crest but functions in second lineage myocardium revealing that this cardiac progenitor field is patterned asymmetrically.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Biomarkers / metabolism
  • Cell Lineage / genetics
  • Cell Lineage / physiology*
  • Heart / embryology*
  • Homeobox Protein PITX2
  • Homeodomain Proteins / genetics
  • Homeodomain Proteins / physiology*
  • Mice
  • Mice, Inbred ICR
  • Mutation
  • Myocardium / cytology
  • Myocardium / metabolism*
  • Neural Crest / metabolism
  • Neural Crest / physiology
  • Nuclear Proteins / genetics
  • Nuclear Proteins / physiology*
  • Transcription Factors

Substances

  • Biomarkers
  • Homeodomain Proteins
  • Nuclear Proteins
  • Transcription Factors