Skip to main content
PMC home page
The Journal of Cell Biology logoLink to The Journal of Cell Biology
. 1996 Nov 2;135(4):1097–1107. doi: 10.1083/jcb.135.4.1097

Healing of incisional wounds in the embryonic chick wing bud: characterization of the actin purse-string and demonstration of a requirement for Rho activation

PMCID: PMC2133375  PMID: 8922389

Abstract

Small skin wounds in the chick embryo do not heal by lamellipodial crawling of cells at the wound edge as a skin wound does in the adult, but rather by contraction of an actin purse-string that rapidly assembles in the front row of epidermal cells (Martin, P., and J. Lewis. 1992. Nature (Lond.). 360:179-183). To observe the early time course of actin purse-string assembly and to characterize other cytoskeletal components of the contractile machinery, we have followed the healing of incisional or slash wounds on the dorsum of the chick wing; these wounds take only seconds to create and heal within approximately 6 h. Healing of the epithelium depends on a combination of purse-string contraction and zipper-like closure of the gap between the cut edges of the epithelium. Confocal laser scanning microscope studies show that actin initially aligns into a cable at the wound margin in the basal layer of the epidermis within approximately 2 min of wounding. Coincident with actin cable assembly, we see localization of cadherins into clusters at the wound margin, presumably marking the sites where segments of the cable in adjacent cells are linked via adherens junctions. A few minutes later we also see localization of myosin II at the wound margin, as expected if myosin is being recruited into the cable to generate a contractile force for wound healing. At the time of wounding, cells at the wound edge become transiently leaky, allowing us to load them with reagents that block the function of two small GTPases, Rho and Rac, which recently have been shown to play key roles in reorganiztion of the actin cytoskeleton in tissue-culture cells (Hall, A. 1994. Annu. Rev. Cell Biol. 10:31-54). Loading wound edge epidermal cells with C3 transferase, a bacterial exoenzyme that inactivates endogenous Rho, prevents assembly of an actin cable and causes a failure of healing. No such effects are seen with N17rac, a dominant inhibitory mutant Rac protein. These findings support the view that in this system the actin cable is required for healing-both the purse-string contraction and the zipping up-and that Rho is required for formation of the actin cable.

Full Text

The Full Text of this article is available as a PDF (7.6 MB).

Selected References

These references are in PubMed. This may not be the complete list of references from this article.

  1. Bement W. M., Forscher P., Mooseker M. S. A novel cytoskeletal structure involved in purse string wound closure and cell polarity maintenance. J Cell Biol. 1993 May;121(3):565–578. doi: 10.1083/jcb.121.3.565. [DOI] [PMC free article] [PubMed] [Google Scholar]
  2. Buck R. C. Cell migration in repair of mouse corneal epithelium. Invest Ophthalmol Vis Sci. 1979 Aug;18(8):767–784. [PubMed] [Google Scholar]
  3. Caplan A. I., Koutroupas S. The control of muscle and cartilage development in the chick limb: the role of differential vascularization. J Embryol Exp Morphol. 1973 Jun;29(3):571–583. [PubMed] [Google Scholar]
  4. Eaton S., Auvinen P., Luo L., Jan Y. N., Simons K. CDC42 and Rac1 control different actin-dependent processes in the Drosophila wing disc epithelium. J Cell Biol. 1995 Oct;131(1):151–164. doi: 10.1083/jcb.131.1.151. [DOI] [PMC free article] [PubMed] [Google Scholar]
  5. Grinnell F. Wound repair, keratinocyte activation and integrin modulation. J Cell Sci. 1992 Jan;101(Pt 1):1–5. doi: 10.1242/jcs.101.1.1. [DOI] [PubMed] [Google Scholar]
  6. Hall A. Small GTP-binding proteins and the regulation of the actin cytoskeleton. Annu Rev Cell Biol. 1994;10:31–54. doi: 10.1146/annurev.cb.10.110194.000335. [DOI] [PubMed] [Google Scholar]
  7. Harden N., Loh H. Y., Chia W., Lim L. A dominant inhibitory version of the small GTP-binding protein Rac disrupts cytoskeletal structures and inhibits developmental cell shape changes in Drosophila. Development. 1995 Mar;121(3):903–914. doi: 10.1242/dev.121.3.903. [DOI] [PubMed] [Google Scholar]
  8. Hariharan I. K., Hu K. Q., Asha H., Quintanilla A., Ezzell R. M., Settleman J. Characterization of rho GTPase family homologues in Drosophila melanogaster: overexpressing Rho1 in retinal cells causes a late developmental defect. EMBO J. 1995 Jan 16;14(2):292–302. doi: 10.1002/j.1460-2075.1995.tb07003.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
  9. Kolega J. Effects of mechanical tension on protrusive activity and microfilament and intermediate filament organization in an epidermal epithelium moving in culture. J Cell Biol. 1986 Apr;102(4):1400–1411. doi: 10.1083/jcb.102.4.1400. [DOI] [PMC free article] [PubMed] [Google Scholar]
  10. Luo L., Liao Y. J., Jan L. Y., Jan Y. N. Distinct morphogenetic functions of similar small GTPases: Drosophila Drac1 is involved in axonal outgrowth and myoblast fusion. Genes Dev. 1994 Aug 1;8(15):1787–1802. doi: 10.1101/gad.8.15.1787. [DOI] [PubMed] [Google Scholar]
  11. Martin P., Lewis J. Actin cables and epidermal movement in embryonic wound healing. Nature. 1992 Nov 12;360(6400):179–183. doi: 10.1038/360179a0. [DOI] [PubMed] [Google Scholar]
  12. Martin P., Lewis J. Origins of the neurovascular bundle: interactions between developing nerves and blood vessels in embryonic chick skin. Int J Dev Biol. 1989 Sep;33(3):379–387. [PubMed] [Google Scholar]
  13. McCluskey J., Martin P. Analysis of the tissue movements of embryonic wound healing--DiI studies in the limb bud stage mouse embryo. Dev Biol. 1995 Jul;170(1):102–114. doi: 10.1006/dbio.1995.1199. [DOI] [PubMed] [Google Scholar]
  14. Paterson H. F., Self A. J., Garrett M. D., Just I., Aktories K., Hall A. Microinjection of recombinant p21rho induces rapid changes in cell morphology. J Cell Biol. 1990 Sep;111(3):1001–1007. doi: 10.1083/jcb.111.3.1001. [DOI] [PMC free article] [PubMed] [Google Scholar]
  15. Ridley A. J., Comoglio P. M., Hall A. Regulation of scatter factor/hepatocyte growth factor responses by Ras, Rac, and Rho in MDCK cells. Mol Cell Biol. 1995 Feb;15(2):1110–1122. doi: 10.1128/mcb.15.2.1110. [DOI] [PMC free article] [PubMed] [Google Scholar]
  16. Ridley A. J., Hall A. The small GTP-binding protein rho regulates the assembly of focal adhesions and actin stress fibers in response to growth factors. Cell. 1992 Aug 7;70(3):389–399. doi: 10.1016/0092-8674(92)90163-7. [DOI] [PubMed] [Google Scholar]
  17. Ridley A. J., Paterson H. F., Johnston C. L., Diekmann D., Hall A. The small GTP-binding protein rac regulates growth factor-induced membrane ruffling. Cell. 1992 Aug 7;70(3):401–410. doi: 10.1016/0092-8674(92)90164-8. [DOI] [PubMed] [Google Scholar]
  18. Tsukita S., Tsukita S., Nagafuchi A., Yonemura S. Molecular linkage between cadherins and actin filaments in cell-cell adherens junctions. Curr Opin Cell Biol. 1992 Oct;4(5):834–839. doi: 10.1016/0955-0674(92)90108-o. [DOI] [PubMed] [Google Scholar]
  19. Wulf E., Deboben A., Bautz F. A., Faulstich H., Wieland T. Fluorescent phallotoxin, a tool for the visualization of cellular actin. Proc Natl Acad Sci U S A. 1979 Sep;76(9):4498–4502. doi: 10.1073/pnas.76.9.4498. [DOI] [PMC free article] [PubMed] [Google Scholar]
  20. Young P. E., Pesacreta T. C., Kiehart D. P. Dynamic changes in the distribution of cytoplasmic myosin during Drosophila embryogenesis. Development. 1991 Jan;111(1):1–14. doi: 10.1242/dev.111.1.1. [DOI] [PubMed] [Google Scholar]

Articles from The Journal of Cell Biology are provided here courtesy of The Rockefeller University Press

RESOURCES