The C. elegans developmental fusogen EFF-1 mediates homotypic fusion in heterologous cells and in vivo.
During cell-cell fusion, two cells' plasma membranes merge, allowing the cytoplasms to mix and form a syncytium. Little is known about the mechanisms of cell fusion. Here, we asked whether eff-1, shown previously to be essential for fusion in Caenorhabditis elegans, acts directly in the fusion machinery. We show that expression of EFF-1 transmembrane protein drives fusion of heterologous cells into multinucleate syncytia. We obtained evidence that EFF-1-mediated fusion involves a hemifusion intermediate characterized by membrane mixing without cytoplasm mixing. Furthermore, syncytiogenesis requires EFF-1 in both fusing cells. To test whether this mechanism also applies in vivo, we conducted genetic mosaic analysis of C. elegans and found that homotypic epidermal fusion requires EFF-1 in both cells. Thus, although EFF-1-mediated fusion shares characteristics with viral and intracellular fusion, including an apparent hemifusion step, it differs from these reactions in the homotypic organization of the fusion machinery.
Podbilewicz
Benjamin
B
Department of Biology, Technion-Israel Institute of Technology, Haifa 32000, Israel. podbilew@tx.technion.ac.il
Leikina
Evgenia
E
Sapir
Amir
A
Valansi
Clari
C
Suissa
Meital
M
Shemer
Gidi
G
Chernomordik
Leonid V
LV
D000818:Animals; D030801:Animals, Genetically Modified; D017173:Caenorhabditis elegans / Q000166:cytology* / Q000196:embryology* / Q000235:genetics / Q000378:metabolism*; D029742:Caenorhabditis elegans Proteins / Q000235:genetics / Q000378:metabolism*; D002459:Cell Fusion; D002462:Cell Membrane / Q000378:metabolism / Q000502:physiology*; D002478:Cells, Cultured; D004625:Embryo, Nonmammalian; D017930:Genes, Reporter; D049452:Green Fluorescent Proteins / Q000378:metabolism; D007700:Kinetics; D008562:Membrane Glycoproteins / Q000235:genetics / Q000378:metabolism*; D008954:Models, Biological; D009030:Mosaicism; D018411:Spodoptera / Q000166:cytology; D013997:Time Factors; D014162:Transfection; D019076:Transgenes
D029742:Caenorhabditis elegans Proteins; C470734:EFF-1 protein, C elegans; D008562:Membrane Glycoproteins; D049452:Green Fluorescent Proteins