Figure 7

Model of myoblast fusion creating the circular and longitudinal visceral muscles and the somatic muscles of the Drosophila embryo. (A) Circular visceral muscles arise by incomplete fusion of one FC (blue nuclei) with one FCM (yellow nuclei, after fusion this nucleus is drawn in brown); this depends on Duf, Rst, Sns, and Mbc. (B) Longitudinal visceral myoblast fusion leads to syncytia, mostly with six nuclei. Duf (blue nuclei) and Sns (yellow nuclei) are specifically expressed according to cell type during this fusion. In the absence of Mbc, no fusion occurs; lack of Rols and Blow leads to a limited number of fusions. (C) During somatic myoblast fusion, lack of Duf, Rst, Sns, and Mbc abolishes fusion almost completely; Rols, Kette, WASp, Wip and Arp3^schwächling are required for further fusion events to form individual muscles with their characteristic nuclei number.