Notch-mediated lateral inhibition is an evolutionarily conserved mechanism patterning the ectoderm in echinoids

• Published in: Development Genes and Evolution Vol. 228; no. 1; pp. 1 - 11
• Main Author: Erkenbrack, Eric M.
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01.01.2018; Springer Nature B.V
• Subjects: Animal Genetics and Genomics; Animals; Biomedical and Life Sciences; Body Patterning; Cell Biology; Cell growth; Cell proliferation; Developmental Biology; early development; Echinoidea; Ectoderm; Ectopic expression; Embryo, Nonmammalian - chemistry; Embryo, Nonmammalian - metabolism; Eucidaris tribuloides; Evolutionary Biology; Gastrulation; genes; Kinases; Life Sciences; messenger RNA; Neural Stem Cells - metabolism; Neuroectoderm; neurons; Notch protein; Original Article; Pattern formation; Plant Genetics and Genomics; Progenitor cells; Receptors, Notch - metabolism; RNA, Messenger - analysis; Sea Urchins - chemistry; Sea Urchins - cytology; Sea Urchins - embryology; Serotonin; Spatial distribution; Supernumerary; Zoology; Gene regulatory networks; Sea urchins; HES proteins; Pigment cells; Notch signaling; Neurogenic ectoderm
• ISSN: 0949-944X; 3059-3239; 1432-041X; 1432-041X; 3059-3247
• DOI: 10.1007/s00427-017-0599-y

Notch signaling is a crucial cog in early development of euechinoid sea urchins, specifying both non-skeletogenic mesodermal lineages and serotonergic neurons in the apical neuroectoderm. Here, the spatial distributions and function of delta , gcm , and hesc , three genes critical to these processes in euechinoids, are examined in the distantly related cidaroid sea urchin Eucidaris tribuloides. Spatial distribution and experimental perturbation of delta and hesc suggest that the function of Notch signaling in ectodermal patterning in early development of E. tr ibuloides is consistent with canonical lateral inhibition. Delta transcripts were observed in t he archenteron, apical ectoderm, and lateral ectoderm in gastrulating e mbryos of E. tribuloides. Perturbation of Notch signaling by either delta morpholino or treatment of DAPT downregulated hesc and upregulated delta and gcm , resulting in ectopic expression of delta and gcm. Similarly, hesc perturbation mirrored the effects of delta perturbation. Interestingly, perturbation of delta or hesc resulted in more cells expressing gcm and supernumerary pigment cells, suggesting that pigment cell proliferation is regulated by Notch in E. tribuloides . These results are consistent with an evolutionary scenario whereby, in the echinoid ancestor, Notch signaling was deployed in the ectoderm to specify neurogenic progenitors and controlled pigment cell proliferation in the dorsal ectoderm.