Specialized extraembryonic cells connect embryonic and extraembryonic epidermis in response to Dpp during dorsal closure in Drosophila

Dev Biol. 2007 Jan 15;301(2):340-9. doi: 10.1016/j.ydbio.2006.09.020. Epub 2006 Sep 16.

Abstract

Dorsal closure in Drosophila embryogenesis involves expansion of the dorsal epidermis, followed by closure of the opposite epidermal edges. This process is driven by contractile force generated by an extraembryonic epithelium covering the yolk syncytium known as the amnioserosa. The secreted signaling molecule Dpp is expressed in the leading edge of the dorsal epidermis and is essential for dorsal closure. We found that the outermost row of amnioserosa cells (termed pAS) maintains a tight basolateral cell-cell adhesion interface with the leading edge of dorsal epidermis throughout the dorsal closure process. pAS was subject to altered cell motility in response to Dpp emanating from the dorsal epidermis, and this response was essential for dorsal closure. alphaPS3 and betaPS integrin subunits accumulated in the interface between pAS and dorsal epidermis, and were both required for dorsal closure. Looking at alphaPS3, type I Dpp receptor, and JNK mutants, we found that pAS cell motility was altered and pAS and dorsal epidermis adhesion failed under the mechanical stress of dorsal closure, suggesting that a Dpp-mediated mechanism connects the squamous pAS to the columnar dorsal epidermis to form a single coherent epithelial layer.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Cell Adhesion
  • Cell Movement
  • Drosophila Proteins / genetics
  • Drosophila Proteins / metabolism*
  • Drosophila melanogaster / cytology
  • Drosophila melanogaster / embryology*
  • Drosophila melanogaster / genetics
  • Drosophila melanogaster / metabolism*
  • Embryo, Nonmammalian / embryology
  • Embryo, Nonmammalian / metabolism
  • Embryonic Development*
  • Epidermal Cells
  • Epidermis / embryology*
  • Epidermis / metabolism*
  • Gene Expression Regulation, Developmental
  • Integrin alpha Chains / genetics
  • JNK Mitogen-Activated Protein Kinases / genetics
  • JNK Mitogen-Activated Protein Kinases / metabolism
  • Microscopy, Electron, Transmission
  • Mutation / genetics
  • Signal Transduction

Substances

  • Drosophila Proteins
  • Integrin alpha Chains
  • dpp protein, Drosophila
  • JNK Mitogen-Activated Protein Kinases