Early changes in the distribution and organization of microfilament proteins during cell transformation

Cell. 1981 Apr;24(1):175-84. doi: 10.1016/0092-8674(81)90513-4.


During the onset of transformation, Rous sarcoma virus-infected cells undergo characteristic morphological changes that reflect the biochemical events induced by the viral src gene. Temperature downshift experiments using chick embryo cells infected with transformation-defective temperature-sensitive viral mutants have shown two major morphological changes occurring at different times in the transformation process: ruffle-like flowers appear on the dorsal cell surface as early as 15 min after temperature shift, while later, between 6 and 12 hr, cytoskeletal stress fibers disappear and the cells round up. We report that flowers contain large accumulations of the cytoskeletal proteins actin, alpha-actinin, myosin and tropomyosin. Furthermore, since flowers stain very intensely with fluorescein-labeled phalloidin, a cyclopeptide that selectively binds to F-actin and not to G-actin, we suggest that these structures result from an early reorganization of microfilaments.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Avian Sarcoma Viruses / genetics*
  • Cell Transformation, Viral*
  • Cells, Cultured
  • Chick Embryo
  • Cytoskeleton / metabolism*
  • Cytoskeleton / ultrastructure
  • Fluorescent Antibody Technique
  • Genes, Viral*
  • Kinetics
  • Luminescent Measurements
  • Microscopy, Electron
  • Viral Proteins / biosynthesis*
  • Viral Proteins / genetics


  • Viral Proteins