Onuma TA, Hayashi M, Gyoja F, Kishi K, Wang K, Nishida H.

Proc Natl Acad Sci U S A. 2020 Feb 25;117(8):4188-4198. doi:10.1073/pnas.1916858117

A chordate species lacking Nodal utilizes calcium oscillation and Bmp for left-right patterning.

“Descendant cells of the L- and R-cells were distributed asymmetrically throughout the organism, even in most morphologically symmetric organs.” “L- and R-cells in the two-cell embryo show stereotyped asymmetries in their cell fates; this is in contrast to ascidian and vertebrate embryos.” “Both oral glands [...] were L-descendants. In contrast, the subchordal cells, [...] were R-descendants. The oral gland and subchordal cells have been proposed to share an ontogenic origin, because only larvacean species with an oral gland have subchordal cells. However, our results suggest that these two cells had a different origin.” “Bmp.a expression was detected in 40% of the R-cells, but none of the L-cells.” “Ca2+ oscillation is required for Bmp.a expression.”