Supplementary Figure 10: Time-lapse imaging of the early stage of development of a Drosophila embryo.

(a) Time sequence of soSPIM optical sections 21.2 µm deep within a Drosophila embryo expressing the nuclear protein histone-mCherry imaged with a 20×/0.5-NA objective and a 4.3-μm-thick light sheet. A 35-µm Z-stack with a 1.35-µm z-step was acquired every 150 s for 220 min. We can observe the nucleus migrating toward the embryo’s outer surface (t = 0 to 52.5 min), further division stages of the nucleus at the outer surface of the embryo (t = 52.5 to 97.5 min) and the beginning of the gastrulation stage of the embryos (t = 190 min) demonstrating the viability of the embryos, despite the few apoptosis cellular events (t = 97.5 min). (b) Upper panel: maximum intensity projection along the z-axis (Z-MIP) at t = 40 min, illustrating the early migration of the nucleus toward the outer surface of the embryo. Lower panel: maximum intensity projection along the y-axis (Y-MIP) at t = 40 min, with segmentation of the nuclei within the embryo (depth is color-coded). Nuclei were detected up to at least 35 µm inside the embryo, illustrating the high penetration depth of the soSPIM method. (c) Three soSPIM optical sections of the embryo at t = 87.5 min, illustrating the development of the embryo as well as the penetration depth. (d) soSPIM optical section at t = 207.5 min and 30-µm depth, illustrating the embryo viability after 207 min of imaging, as the embryo is about to enter gastrulation. Scale bars, 50 µm.