title: Genetic control of fusion pore expansion in the epidermis of Caenorhabditis elegans.
abstract: Developmental cell fusion is found in germlines, muscles, bones, placentae, and stem cells. In Caenorhabditis elegans 300 somatic cells fuse during development. Although there is extensive information on the early intermediates of viral-induced and intracellular membrane fusion, little is known about late stages in membrane fusion. To dissect the pathway of cell fusion in C. elegans embryos, we use genetic and kinetic analyses using live-confocal and electron microscopy. We simultaneously monitor the rates of multiple cell fusions in developing embryos and find kinetically distinct stages of initiation and completion of membrane fusion in the epidermis. The stages of cell fusion are differentially blocked or retarded in eff-1 and idf-1 mutants. We generate kinetic cell fusion maps for embryos grown at different temperatures. Different sides of the same cell differ in their fusogenicity: the left and right membrane domains are fusion-incompetent, whereas the anterior and posterior membrane domains fuse with autonomous kinetics in embryos. All but one cell pair can initiate the formation of the largest syncytium. The first cell fusion does not trigger a wave of orderly fusions in either direction. Ultrastructural studies show that epidermal syncytiogenesis require eff-1 activities to initiate and expand membrane merger.
authors.affiliation: Department of Biology, Technion-Israel Institute of Technology, Haifa 32000, Israel.
authors.forename: Tamar
authors.initials: T
authors.lastname: Gattegno
authors.forename: Aditya
authors.initials: A
authors.lastname: Mittal
authors.forename: Clari
authors.initials: C
authors.lastname: Valansi
authors.forename: Ken C Q
authors.initials: KC
authors.lastname: Nguyen
authors.forename: David H
authors.initials: DH
authors.lastname: Hall
authors.forename: Leonid V
authors.initials: LV
authors.lastname: Chernomordik
authors.forename: Benjamin
authors.initials: B
authors.lastname: Podbilewicz
mesh_terms: D000818:Animals; D017173:Caenorhabditis elegans / Q000196:embryology / Q000235:genetics*; D029742:Caenorhabditis elegans Proteins / Q000235:genetics* / Q000378:metabolism; D002459:Cell Fusion; D004625:Embryo, Nonmammalian; D000078404:Epidermal Cells; D004817:Epidermis / Q000196:embryology / Q000502:physiology / Q000648:ultrastructure; D018507:Gene Expression Regulation, Developmental; D015726:Giant Cells / Q000166:cytology / Q000502:physiology; D007700:Kinetics; D008562:Membrane Glycoproteins / Q000235:genetics / Q000378:metabolism; D009154:Mutation; D013696:Temperature
chemical_list: D029742:Caenorhabditis elegans Proteins; C470734:EFF-1 protein, C elegans; D008562:Membrane Glycoproteins