Epicardial spindle orientation controls cell entry into the myocardium

Dev Cell. 2010 Jul 20;19(1):114-25. doi: 10.1016/j.devcel.2010.06.011.

Abstract

During heart morphogenesis, epicardial cells undergo an epithelial-to-mesenchymal transition (EMT) and migrate into the subepicardium. The cellular signals controlling this process are poorly understood. Here, we show that epicardial cells exhibit two distinct mitotic spindle orientations, directed either parallel or perpendicular to the basement membrane. Cells undergoing perpendicular cell division subsequently enter the myocardium. We found that loss of beta-catenin led to a disruption of adherens junctions and a randomization of mitotic spindle orientation. Loss of adherens junctions also disrupted Numb localization within epicardial cells, and disruption of Numb and Numblike expression in the epicardium led to randomized mitotic spindle orientations. Taken together, these data suggest that directed mitotic spindle orientation contributes to epicardial EMT and implicate a junctional complex of beta-catenin and Numb in the regulation of spindle orientation.

Publication types

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

MeSH terms

  • Adherens Junctions / metabolism
  • Adherens Junctions / ultrastructure
  • Animals
  • Cell Movement / physiology
  • Cell Polarity / physiology
  • Cell Proliferation
  • Female
  • Heart / embryology
  • Membrane Proteins / metabolism
  • Mice
  • Mice, Knockout
  • Mice, Transgenic
  • Myocardium / cytology*
  • Myocardium / metabolism
  • Nerve Tissue Proteins / deficiency
  • Nerve Tissue Proteins / genetics
  • Nerve Tissue Proteins / metabolism
  • Pericardium / cytology*
  • Pericardium / embryology*
  • Pericardium / metabolism
  • Pregnancy
  • Spindle Apparatus / metabolism
  • Spindle Apparatus / ultrastructure*
  • beta Catenin / metabolism

Substances

  • CTNNB1 protein, mouse
  • Membrane Proteins
  • Nerve Tissue Proteins
  • Numb protein, mouse
  • Numbl protein, mouse
  • beta Catenin