title: Tissue fusion over nonadhering surfaces.
abstract: Tissue fusion eliminates physical voids in a tissue to form a continuous structure and is central to many processes in development and repair. Fusion events in vivo, particularly in embryonic development, often involve the purse-string contraction of a pluricellular actomyosin cable at the free edge. However, in vitro, adhesion of the cells to their substrate favors a closure mechanism mediated by lamellipodial protrusions, which has prevented a systematic study of the purse-string mechanism. Here, we show that monolayers can cover well-controlled mesoscopic nonadherent areas much larger than a cell size by purse-string closure and that active epithelial fluctuations are required for this process. We have formulated a simple stochastic model that includes purse-string contractility, tissue fluctuations, and effective friction to qualitatively and quantitatively account for the dynamics of closure. Our data suggest that, in vivo, tissue fusion adapts to the local environment by coordinating lamellipodial protrusions and purse-string contractions.
authors.affiliation: Laboratoire Physico-Chimie Curie, Institut Curie, Centre de Recherche, Paris Sciences et Lettres Research University, Centre National de la Recherche Scientifique, Université Pierre et Marie Curie, Sorbonne Universités, 75248 Paris, France.
authors.forename: Vincent
authors.initials: V
authors.lastname: Nier
authors.affiliation: Laboratoire Physico-Chimie Curie, Institut Curie, Centre de Recherche, Paris Sciences et Lettres Research University, Centre National de la Recherche Scientifique, Université Pierre et Marie Curie, Sorbonne Universités, 75248 Paris, France Laboratoire PhysicoChimie Curie, Institut Curie, Equipe labellisée Ligue Contre le Cancer, 75248 Paris, France.
authors.forename: Maxime
authors.initials: M
authors.lastname: Deforet
authors.affiliation: Laboratoire Physico-Chimie Curie, Institut Curie, Centre de Recherche, Paris Sciences et Lettres Research University, Centre National de la Recherche Scientifique, Université Pierre et Marie Curie, Sorbonne Universités, 75248 Paris, France Laboratoire PhysicoChimie Curie, Institut Curie, Equipe labellisée Ligue Contre le Cancer, 75248 Paris, France.
authors.forename: Guillaume
authors.initials: G
authors.lastname: Duclos
authors.affiliation: Laboratoire Physico-Chimie Curie, Institut Curie, Centre de Recherche, Paris Sciences et Lettres Research University, Centre National de la Recherche Scientifique, Université Pierre et Marie Curie, Sorbonne Universités, 75248 Paris, France Laboratoire PhysicoChimie Curie, Institut Curie, Equipe labellisée Ligue Contre le Cancer, 75248 Paris, France.
authors.forename: Hannah G
authors.initials: HG
authors.lastname: Yevick
authors.affiliation: Laboratoire Physico-Chimie Curie, Institut Curie, Centre de Recherche, Paris Sciences et Lettres Research University, Centre National de la Recherche Scientifique, Université Pierre et Marie Curie, Sorbonne Universités, 75248 Paris, France Laboratoire PhysicoChimie Curie, Institut Curie, Equipe labellisée Ligue Contre le Cancer, 75248 Paris, France.
authors.forename: Olivier
authors.initials: O
authors.lastname: Cochet-Escartin
authors.affiliation: Laboratoire Physico-Chimie Curie, Institut Curie, Centre de Recherche, Paris Sciences et Lettres Research University, Centre National de la Recherche Scientifique, Université Pierre et Marie Curie, Sorbonne Universités, 75248 Paris, France pascal.silberzan@curie.fr philippe.marcq@curie.fr.
authors.forename: Philippe
authors.initials: P
authors.lastname: Marcq
authors.affiliation: Laboratoire Physico-Chimie Curie, Institut Curie, Centre de Recherche, Paris Sciences et Lettres Research University, Centre National de la Recherche Scientifique, Université Pierre et Marie Curie, Sorbonne Universités, 75248 Paris, France Laboratoire PhysicoChimie Curie, Institut Curie, Equipe labellisée Ligue Contre le Cancer, 75248 Paris, France pascal.silberzan@curie.fr philippe.marcq@curie.fr.
authors.forename: Pascal
authors.initials: P
authors.lastname: Silberzan
mesh_terms: D000205:Actomyosin / Q000378:metabolism; D000818:Animals; D002448:Cell Adhesion; D004285:Dogs; D004847:Epithelial Cells / Q000166:cytology; D004848:Epithelium / Q000502:physiology; D053685:Laser Therapy; D061985:Madin Darby Canine Kidney Cells; D008954:Models, Biological; D038081:Organogenesis; D013269:Stochastic Processes; D013499:Surface Properties; D014945:Wound Healing
chemical_list: D000205:Actomyosin
keywords: epithelial fluctuations; purse string contraction; tissue fusion; wound closure