title: Dynamic analysis of filopodial interactions during the zippering phase of Drosophila dorsal closure.
abstract: Dorsal closure is a paradigm epithelial fusion episode that occurs late in Drosophila embryogenesis and leads to sealing of a midline hole by bonding of two opposing epithelial sheets. The leading edge epithelial cells express filopodia and fusion is dependent on interdigitation of these filopodia to prime formation of adhesions. Since the opposing epithelia are molecularly patterned there must exist some mechanism for accurately aligning the two sheets across this fusion seam. To address this, we generated a fly in which RFP-Moesin and GFP-Moesin are expressed in mutually exclusive stripes within each segment using the engrailed and patched promoters. We observe mutually exclusive interactions between the filopodia of engrailed and patched cells. Interactions between filopodia from matching cells leads to formation of tethers between them, and these tethers can pull misaligned epithelial sheets into alignment. Filopodial matching also occurs during repair of laser wounds in the ventral epithelium, and so this behaviour is not restricted to leading edge cells during dorsal closure. Finally, we characterise the behaviour of a patched-expressing cell that we observe within the engrailed region of segments A1-A5, and provide evidence that this cell contributes to cell matching.
authors.affiliation: Department of Biochemistry, School of Medical Sciences, University of Bristol, University Walk, Bristol BS8 1DA, UK. tom.millard@manchester.ac.uk
authors.forename: Thomas H
authors.initials: TH
authors.lastname: Millard
authors.forename: Paul
authors.initials: P
authors.lastname: Martin
mesh_terms: D000818:Animals; D001426:Bacterial Proteins / Q000378:metabolism; D019521:Body Patterning; D029721:Drosophila Proteins; D004331:Drosophila melanogaster / Q000166:cytology* / Q000196:embryology*; D004625:Embryo, Nonmammalian / Q000166:cytology / Q000196:embryology / Q000378:metabolism; D047108:Embryonic Development; D004848:Epithelium / Q000196:embryology; D049452:Green Fluorescent Proteins / Q000378:metabolism; D018398:Homeodomain Proteins / Q000378:metabolism; D008164:Luminescent Proteins / Q000378:metabolism; D008840:Microfilament Proteins / Q000378:metabolism; D000072079:Patched Receptors; D011554:Pseudopodia / Q000378:metabolism*; D011956:Receptors, Cell Surface / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D014157:Transcription Factors / Q000378:metabolism; D014945:Wound Healing
chemical_list: D001426:Bacterial Proteins; D029721:Drosophila Proteins; C063459:En protein, Drosophila; D018398:Homeodomain Proteins; D008164:Luminescent Proteins; D008840:Microfilament Proteins; D000072079:Patched Receptors; D011956:Receptors, Cell Surface; D011993:Recombinant Fusion Proteins; D014157:Transcription Factors; C054562:yellow fluorescent protein, Bacteria; C071058:moesin; D049452:Green Fluorescent Proteins