MyoD converts primary dermal fibroblasts, chondroblasts, smooth muscle, and retinal pigmented epithelial cells into striated mononucleated myoblasts and multinucleated myotubes

Academic Article

Abstract

  • Shortly after their birth, postmitotic mononucleated myoblasts in myotomes, limb buds, and conventional muscle cultures elongate and assemble a cohort of myofibrillar proteins into definitively striated myofibrils. MyoD induces a number of immortalized and/or transformed nonmuscle cells to express desmin and several myofibrillar proteins and to fuse into myosacs. We now report that MyoD converts normal dermal fibroblasts, chondroblasts, gizzard smooth muscle, and pigmented retinal epithelial cells into elongated postmitotic mononucleated striated myoblasts. The sarcomeric localization of antibodies to desmin, α-actinin, titin, troponin-I, α-actin, myosin heavy chain, and myomesin in these converted myoblasts are indistinguishable from in vivo and in vitro normal myoblasts. Converted myoblasts fuse into typical anisodiametric multinucleated myotubes that often contract spontaneously. Conversion and subsequent expression of the skeletal myogenic program are autonomous events, occurring in four nonmuscle microenvironments consisting of different combinations of foreign extracellular matrix molecules. Early events associated with conversion by MyoD involve (i) withdrawal from the cell cycle, (ii) down-regulation of the subverted cell's ongoing differentiation program, and (iii) initiation of desmin synthesis in presumptive myoblasts and dramatic redistribution of microtubules and desmin intermediate filaments in postmitotic myoblasts.
  • Authors

    Digital Object Identifier (doi)

    Author List

  • Choi J; Costa ML; Mermelstein CS; Chagas C; Holtzer S; Holtzer H
  • Start Page

  • 7988
  • End Page

  • 7992
  • Volume

  • 87
  • Issue

  • 20