Fig. S2

Fig. S2

Targeted labeling of the ventral somite by Kaede photoconversion.

(A, B) Wild-type embryos injected with Kaede mRNA were photoconverted at 18 hpf in the ventral portion of one single somite, corresponding to the presumptive ventral sclerotome domain, as described in Fig 1C. Embryos (n = 9) were fixed and sectioned to examine the photoconverted region in cross-sections (A). Alternatively, embryos (n = 5) were remounted and imaged from the dorsal side. The resulting confocal stacks were 3D reconstructed to show transverse views of the photoconverted region (B). Strong Kaede^red signal (arrows) is restricted to the ventral portion of targeted somites (solid outlines), whereas deeper tissues are only weakly labeled (arrowheads). Note that a small patch of the skin (asterisks), corresponding to the point of laser entry, is also labeled by Kaede^red. The neural tube (NT) and notochord (n) are indicated by dotted lines. (C) Corresponding color-coded depth projections of images shown in Fig 1D. At 24 hpf and 40 hpf, most Kaede^red cells (arrowheads) are found deeper in the fish compared to the photoconverted ventral somite. Deeper cells are indicated by red/magenta colors, while more superficial cells are represented by green/cyan colors. n = 35 embryos. Scale bars: 50 μm.