Fig. 2

Myomaker is not required cell autonomously for myocyte fusion. A: A portion of donor myomaker^sq36 mutant cells transplanted into wild-type host can undergo myocyte fusion. The image shows a rhodamine-labeled donor mutant cell, which also expresses H2B-GFP in its nuclei, that underwent fusion to form a multinucleated cell with 6 nuclei (indicated by triangles), and a rhodamine-labeled donor mutant cell that did not undergo fusion and remained mononucleated (indicated by an arrow). All nuclei and cell membranes are stained with DAPI and anti-β-catenin antibodies respectively, while H2B-GFP is labeled with anti-GFP staining. The image is a projection of 2 Z-sections. Scale bar=20 µm. B: Some donor wild-type cells are able to fuse with myomaker^sq36mutant cells when transplanted into the myomaker^sq36 mutant host. Top panel shows a rhodamine-labeled multinucleated chimeric cell expressing H2B-GFP in all its nuclei (indicated by triangles). The chimeric cell resulted from fusion between rhodamine-labeled donor wild-type cell and host mutant cells that express H2B-GFP in the nuclei. The bottom panel shows a rhodamine-labeled donor wild-type cell that did not undergo fusion and remained mononucleated (indicated by an arrow). Nuclei and cell membranes are stained with DAPI and anti-β-catenin antibodies respectively, while H2B-GFP is labeled with anti-GFP staining. The top and bottom panel images are projections of 5 and 3 Z-sections respectively. Scale bar=20 µm.