The role of PILMACs and of the genes bubbles and schwächling during muscle development in Drosophila melanogaster

• Applicant: Professorin Dr. Renate Renkawitz-Pohl
• Subject Area: Developmental Biology
• Term: from 2006 to 2014
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 27889892

During Drosophila embryogenesis, the muscle pattern is established and cell-cell fusion leads to multinucleated myotubes. Fusion-competent myoblasts (FCMs) fuse to founder cells (FCs)/growing myotubes. With Ribokinase (entry into ATP synthesis), we identified a new essential biochemical pathway for myogenesis with respect to Founder Cell (FC) determination and fusion. Looking at the individual site of fusion, FuRMASs are established, transient cell adhesion structures with signalling properties. Here, cell adhesion molecules, signalling molecules, F- actin, and its regulators do accumulate. At the ultrastructural level the individual fusion site is characterised by a cloud of vesicles at the opposing membranes over an area of 1mm2, named prefusion complex. Importantly, we identified two new components of the FuRMAS: 1) Tetraspanins as candidates for clustering of fusion-relevant molecules at the opposing membranes, and 2) Kosh, an EF hand, putatively Ca2+-binding protein. As a likely candidate for membrane bending during fusion, we identified a gene, which is predicted to encode a C2 domain protein with two putative transmembrane domains. Our central goals are the functional analysis of these newly identified fusion-relevant molecules and their integration into the fusion-relevant signalling cascades with respect to the topology of the FuRMASs.

• DFG Programme: Research Grants