Figure 3

Rare SDECs emerge from trunk somites and migrate to the dorsal aorta.

(A–D) Tg(actb2:nls-Eos); Tg(fli1:eGFP)^y1 embryos were collected at developmental stages ranging from 4 to 18 ss. (A) Newly developed posterior somite pairs were selected by setting a region of interest and photoconverted by UV light. (A’) A sagittal section through a pair of converted somite showing somite-specific conversion and lack of converted LPM-derived ECs. (B) At 32 hpf, embryos were laterally staged, and images of the dorsal aorta taken. SDECS were quantified in the dorsal aorta by examining individual z-stacks and visualizing colocalization of fli1⁺; actb2:nlsEos^RFP converted cells in Tg(actb2:nls-Eos); Tg(fli1:eGFP)^y1 embryos (Ci-Cv). In fli1:eGFP ^- embryos, we identified SDECs by observing actb2:nlsEos^RFP cells on the floor of the DA based on the brightfield channel. (D) We observed that trunk somites (numbers 5–18), located above the yolk tube extension, generated the most SDECs. Each somite pair contributed between 0–6 SDECs to the DA. s, somites; DA, dorsal aorta. In each converted somite pair, n≥6, with each point representing the SDEC count from one embryo. The median for each somite pair is indicated as a column, and the standard error of the mean (SEM) is indicated as an error bar.