Fig. 3

Validation of novel cell states. A–D In situ hybridation at stage 12 for the indicated markers. A MsxB is expressed throughout the b-line neuromesodermal territory and is included as a landmark. It is also expressed in the sibling dorsal midline tail epidermal cells but this expression is more lateral and cannot be clearly seen in this dorsal view. B RGS3/5/8 is expressed in the more anterior b8.19 lineage. C Fam167 is expressed in the more posterior b8.17 lineage. D Neurogenin was consistently expressed in posterior marginal b-line cells believed to be b9.41 and b9.49. It is also expressed in its well-characterized pattern in A9.32 and A9.31. There was occasional expression in a cell just anterior to b9.41 likely to be part of the dorsal midline tail epidermal precursors that are known to express neurogenin at a slightly later stage [58]. E Stage 12.5 embryo electroporated with a neurogenin (b-line) reporter construct driving expression of a Histone H2B Venus fluorescent protein fusion. Mosaic expression is seen in two posterior marginal blastomeres believed to be b9.41 and b9.49 (white arrowheads). Reporter signal is shown in green and phalloidin in white. The embryos in all panels are oriented with anterior to the top and the vegetal pole towards the viewer