The actin regulator N-WASp is required for muscle-cell fusion in mice

Proc Natl Acad Sci U S A. 2012 Jul 10;109(28):11211-6. doi: 10.1073/pnas.1116065109. Epub 2012 Jun 26.


A fundamental aspect of skeletal myogenesis involves extensive rounds of cell fusion, in which individual myoblasts are incorporated into growing muscle fibers. Here we demonstrate that N-WASp, a ubiquitous nucleation-promoting factor of branched microfilament arrays, is an essential contributor to skeletal muscle-cell fusion in developing mouse embryos. Analysis both in vivo and in primary satellite-cell cultures, shows that disruption of N-WASp function does not interfere with the program of skeletal myogenic differentiation, and does not affect myoblast motility, morphogenesis and attachment capacity. N-WASp-deficient myoblasts, however, fail to fuse. Furthermore, our analysis suggests that myoblast fusion requires N-WASp activity in both partners of a fusing myoblast pair. These findings reveal a specific role for N-WASp during mammalian myogenesis. WASp-family elements appear therefore to act as universal mediators of the myogenic cell-cell fusion mechanism underlying formation of functional muscle fibers, in both vertebrate and invertebrate species.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Actins / metabolism*
  • Animals
  • Cell Differentiation
  • Cell Fusion
  • Cells, Cultured
  • Crosses, Genetic
  • Drosophila
  • Gene Expression Regulation, Developmental*
  • Heterozygote
  • Mice
  • Mice, Inbred ICR
  • Models, Biological
  • Muscle Development
  • Muscles / cytology*
  • Muscles / embryology
  • Time Factors
  • Wiskott-Aldrich Syndrome Protein, Neuronal / metabolism*


  • Actins
  • Wiskott-Aldrich Syndrome Protein, Neuronal