{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,8]],"date-time":"2026-10-08T02:16:31Z","timestamp":1791425791479,"version":"4.3.3"},"reference-count":43,"publisher":"The Company of Biologists","issue":"8","content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":[],"published-print":{"date-parts":[[2008,4,15]]},"abstract":"<jats:p>Myoblast fusion takes place in two steps in mammals and in Drosophila. First, founder cells (FCs) and fusion-competent myoblasts (FCMs) fuse to form a trinucleated precursor, which then recruits further FCMs. This process depends on the formation of the fusion-restricted myogenic-adhesive structure (FuRMAS), which contains filamentous actin (F-actin) plugs at the sites of cell contact. Fusion relies on the HEM2 (NAP1) homolog Kette, as well as Blow and WASP, a member of the Wiskott-Aldrich-syndrome protein family. Here, we show the identification and characterization of schwa\u0308chling \u2013 a new Arp3-null allele. Ultrastructural analyses demonstrate that Arp3schwa\u0308chling mutants can form a fusion pore, but fail to integrate the fusing FCM. Double-mutant experiments revealed that fusion is blocked completely in Arp3 and wasp double mutants, suggesting the involvement of a further F-actin regulator. Indeed, double-mutant analyses with scar\/WAVE and with the WASP-interacting partner vrp1 (sltr, wip)\/WIP show that the F-actin regulator scar also controls F-actin formation during myoblast fusion. Furthermore, the synergistic phenotype observed in Arp3 wasp and in scar vrp1 double mutants suggests that WASP and SCAR have distinct roles in controlling F-actin formation. From these findings we derived a new model for actin regulation during myoblast fusion.<\/jats:p>","DOI":"10.1242\/jcs.022269","type":"journal-article","created":{"date-parts":[[2008,4,3]],"date-time":"2008-04-03T16:13:37Z","timestamp":1207239217000},"page":"1303-1313","source":"Crossref","is-referenced-by-count":91,"title":["WASP and SCAR have distinct roles in activating the Arp2\/3 complex during myoblast fusion"],"prefix":"10.1242","volume":"121","author":[{"given":"Susanne","family":"Berger","sequence":"first","affiliation":[{"name":"Fachbereich Biologie, Entwicklungsbiologie, Philipps-Universita\u0308t Marburg, Karl-von-Frisch Str. 8, D-35043 Marburg, Germany"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Gritt","family":"Scha\u0308fer","sequence":"additional","affiliation":[{"name":"Fachbereich Biologie, Entwicklungsbiologie, Philipps-Universita\u0308t Marburg, Karl-von-Frisch Str. 8, D-35043 Marburg, Germany"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Do\u0308rthe A.","family":"Kesper","sequence":"additional","affiliation":[{"name":"Fachbereich Biologie, Entwicklungsbiologie, Philipps-Universita\u0308t Marburg, Karl-von-Frisch Str. 8, D-35043 Marburg, Germany"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Anne","family":"Holz","sequence":"additional","affiliation":[{"name":"Institut fu\u0308r Allgemeine und Spezielle Zoologie, Stephanstr. 24, Justus-Liebig-Universita\u0308t Giessen, D-35390 Giessen, Germany"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Therese","family":"Eriksson","sequence":"additional","affiliation":[{"name":"UCMP, Umea\u030a University, Building 6L, 90187 Umea\u030a, Sweden"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Ruth H.","family":"Palmer","sequence":"additional","affiliation":[{"name":"UCMP, Umea\u030a University, Building 6L, 90187 Umea\u030a, Sweden"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Lothar","family":"Beck","sequence":"additional","affiliation":[{"name":"Fachbereich Biologie, Spezielle Zoologie, Philipps-Universita\u0308t Marburg, Karl-von-Frisch Str. 8, D-35043 Marburg, Germany"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Christian","family":"Kla\u0308mbt","sequence":"additional","affiliation":[{"name":"Institut fu\u0308r Neurobiologie, Westfa\u0308lische Wilhelms-Universita\u0308t Mu\u0308nster, Badestr. 9, D-48149 Mu\u0308nster, Germany"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Renate","family":"Renkawitz-Pohl","sequence":"additional","affiliation":[{"name":"Fachbereich Biologie, Entwicklungsbiologie, Philipps-Universita\u0308t Marburg, Karl-von-Frisch Str. 8, D-35043 Marburg, Germany"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Susanne-Filiz","family":"O\u0308nel","sequence":"additional","affiliation":[{"name":"Fachbereich Biologie, Entwicklungsbiologie, Philipps-Universita\u0308t Marburg, Karl-von-Frisch Str. 8, D-35043 Marburg, Germany"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"237","reference":[{"key":"2021042520335368600_REF1","doi-asserted-by":"crossref","unstructured":"Abmayr, S. 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Development128, 5061-5073."},{"key":"2021042520335368600_REF29","doi-asserted-by":"crossref","unstructured":"Richardson, B. E., Beckett, K., Nowak, S. J. and Baylies, M. K. (2007). SCAR\/WAVE and ARp2\/3 are crucial for cytoskeletal remodeling at the site of myoblast fusion. Development134, 4357-4367.","DOI":"10.1242\/dev.010678"},{"key":"2021042520335368600_REF30","doi-asserted-by":"crossref","unstructured":"Robinson, R. C., Turbedsky, K., Kaiser, D. A., Marchand, J. B., Higgs, H. N., Choe, S. and Pollard, T. D. (2001). Crystal structure of Arp2\/3 complex. Science294, 1679-1684.","DOI":"10.1126\/science.1066333"},{"key":"2021042520335368600_REF31","doi-asserted-by":"crossref","unstructured":"Rohatgi, R., Ma, L., Miki, H., Lopez, M., Kirchhausen, T., Takenawa, T. and Kirschner, M. W. (1999). The interaction between N-WASP and the Arp2\/3 complex links Cdc42-dependent signals to actin assembly. Cell97, 221-231.","DOI":"10.1016\/S0092-8674(00)80732-1"},{"key":"2021042520335368600_REF32","doi-asserted-by":"crossref","unstructured":"Ruiz-Gomez, M., Coutts, N., Price, A., Taylor, M. V. and Bate, M. (2000). Drosophila dumbfounded: a myoblast attractant essential for fusion. Cell102, 189-198.","DOI":"10.1016\/S0092-8674(00)00024-6"},{"key":"2021042520335368600_REF33","doi-asserted-by":"crossref","unstructured":"Scha\u0308fer, G., Weber, S., Holz, A., Bogdan, S., Schumacher, S., Mu\u0308ller, A., Renkawitz-Pohl, R. and O\u0308nel, S. F. (2007). The Wiskott-Aldrich syndrome protein (WASP) is essential for myoblast fusion in Drosophila. Dev. Biol.304, 664-674.","DOI":"10.1016\/j.ydbio.2007.01.015"},{"key":"2021042520335368600_REF34","doi-asserted-by":"crossref","unstructured":"Schro\u0308ter, R. H., Lier, S., Holz, A., Bogdan, S., Kla\u0308mbt, C., Beck, L. and Renkawitz-Pohl, R. (2004). kette and blown fuse interact genetically during the second fusion step of myogenesis in Drosophila.Development131, 4501-4509.","DOI":"10.1242\/dev.01309"},{"key":"2021042520335368600_REF35","unstructured":"Schro\u0308ter, R. H., Buttgereit, D., Beck, L., Holz, A. and Renkawitz-Pohl, R. (2006). Blown fuse regulates morphogenesis but not myoblast fusion of the circular visceral muscles in Drosophila.Differentiation74, 1-14."},{"key":"2021042520335368600_REF36","doi-asserted-by":"crossref","unstructured":"Srinivas, B. P., Woo, J., Leong, W. Y. and Roy, S. (2007). A conserved molecular pathway mediates myoblast fusion in insects and vertebrates. Nat. Genet.39, 781-786.","DOI":"10.1038\/ng2055"},{"key":"2021042520335368600_REF37","unstructured":"Stru\u0308nkelnberg, M., Bonengel, B., Moda, L. M., Hertenstein, A., de Couet, H. G., Ramos, R. G. and Fischbach, K. F. (2001). rst and its paralogue kirre act redundantly during embryonic muscle development in Drosophila.Development128, 4229-4239."},{"key":"2021042520335368600_REF38","doi-asserted-by":"crossref","unstructured":"Takenawa, T. and Miki, H. (2001). WASP and WAVE family proteins: key molecules for rapid rearrangement of cortical actin filaments and cell movement. J. Cell Sci.114, 1801-1809.","DOI":"10.1242\/jcs.114.10.1801"},{"key":"2021042520335368600_REF39","doi-asserted-by":"crossref","unstructured":"Tautz, D. and Pfeifle, C. (1989). A non-radioactive in situ hybridization method for the localization of specific RNAs in Drosophila embryos reveals translational control of the segmentation gene hunchback.Chromosoma98, 81-85.","DOI":"10.1007\/BF00291041"},{"key":"2021042520335368600_REF40","doi-asserted-by":"crossref","unstructured":"Taylor, M. V. (2000). Muscle development: molecules of myoblast fusion. Curr. 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