title: Surface apposition and multiple cell contacts promote myoblast fusion in Drosophila flight muscles.
abstract: Fusion of individual myoblasts to form multinucleated myofibers constitutes a widely conserved program for growth of the somatic musculature. We have used electron microscopy methods to study this key form of cell-cell fusion during development of the indirect flight muscles (IFMs) of Drosophila melanogaster. We find that IFM myoblast-myotube fusion proceeds in a stepwise fashion and is governed by apparent cross talk between transmembrane and cytoskeletal elements. Our analysis suggests that cell adhesion is necessary for bringing myoblasts to within a minimal distance from the myotubes. The branched actin polymerization machinery acts subsequently to promote tight apposition between the surfaces of the two cell types and formation of multiple sites of cell-cell contact, giving rise to nascent fusion pores whose expansion establishes full cytoplasmic continuity. Given the conserved features of IFM myogenesis, this sequence of cell interactions and membrane events and the mechanistic significance of cell adhesion elements and the actin-based cytoskeleton are likely to represent general principles of the myoblast fusion process.
authors.affiliation: Department of Molecular Genetics, Weizmann Institute of Science, Rehovot 76100, Israel National Centre for Biological Sciences, Tata Institute of Fundamental Research, Bangalore, Karnataka 560065, India Manipal University, Manipal, Karnataka 576104, India.
authors.forename: Nagaraju
authors.initials: N
authors.lastname: Dhanyasi
authors.affiliation: Department of Molecular Genetics, Weizmann Institute of Science, Rehovot 76100, Israel.
authors.forename: Dagan
authors.initials: D
authors.lastname: Segal
authors.affiliation: Department of Chemical Research Support, Weizmann Institute of Science, Rehovot 76100, Israel.
authors.forename: Eyal
authors.initials: E
authors.lastname: Shimoni
authors.affiliation: Department of Chemical Research Support, Weizmann Institute of Science, Rehovot 76100, Israel.
authors.forename: Vera
authors.initials: V
authors.lastname: Shinder
authors.affiliation: Department of Molecular Genetics, Weizmann Institute of Science, Rehovot 76100, Israel Eyal.Schejter@weizmann.ac.il vijay@ncbs.res.in benny.shilo@weizmann.ac.il.
authors.forename: Ben-Zion
authors.initials: BZ
authors.lastname: Shilo
authors.affiliation: National Centre for Biological Sciences, Tata Institute of Fundamental Research, Bangalore, Karnataka 560065, India Eyal.Schejter@weizmann.ac.il vijay@ncbs.res.in benny.shilo@weizmann.ac.il.
authors.forename: K
authors.initials: K
authors.lastname: VijayRaghavan
authors.affiliation: Department of Molecular Genetics, Weizmann Institute of Science, Rehovot 76100, Israel Eyal.Schejter@weizmann.ac.il vijay@ncbs.res.in benny.shilo@weizmann.ac.il.
authors.forename: Eyal D
authors.initials: ED
authors.lastname: Schejter
mesh_terms: D051376:Actin-Related Protein 2-3 Complex / Q000378:metabolism; D000199:Actins / Q000378:metabolism / Q000648:ultrastructure; D000818:Animals; D002448:Cell Adhesion; D002450:Cell Communication; D002459:Cell Fusion; D002462:Cell Membrane / Q000502:physiology / Q000648:ultrastructure; D022081:Cell Surface Extensions / Q000378:metabolism; D029721:Drosophila Proteins / Q000378:metabolism / Q000648:ultrastructure; D004331:Drosophila melanogaster / Q000166:cytology* / Q000378:metabolism; D005426:Flight, Animal; D009132:Muscles / Q000166:cytology; D032446:Myoblasts / Q000502:physiology* / Q000648:ultrastructure
chemical_list: D051376:Actin-Related Protein 2-3 Complex; D000199:Actins; D029721:Drosophila Proteins