Plan apochromat 1.4 na 100x oil objective

All myofiber imaging was carried out on a Zeiss LSM 880 AxioObserver microscope with Airyscan using a Plan-Apochromat 1.3 NA 40x oil objective (Fig. 1, 2, 3, 4, 5, S1, S2, S3, S4, S5, S6, Video S2, Video S3), a Plan-Apochromat 1.4 NA 63x oil objective (Fig. S1A, Video S1), or a Plan-Apochromat 1.4 NA 100x oil objective (Fig. S3B andS3C). Airyscan processing was performed on all images in Zeiss ZEN software. Z-stacks were acquired at 0.5 μm intervals. Myoblast and myotube imaging was carried out on a Zeiss LSM 880 AxioObserver microscope using wide field fluorescence illumination, a Plan-Apochromat 1.4 NA 100x oil objective, and Zeiss AxioCam monochrome camera (Fig. 3I). Z-stacks through myoblasts and myotubes were acquired at 0.5 μm intervals.