SEA URCHIN RESEARCH: MILESTONES, MEMORIES, AND FUTURE CHALLENGES

Abstract

The sea urchin eggs and embryos have been used for nearly two centuries as experimental models for classical and modern developmental biology. In the late 1870s, the ground-breaking observations independently obtained by Hertwig and Fol highlighted for the first time that a single sperm enters the oocyte and the male and female pronuclei fuse at fertilization.1 From that point on, the seminal studies of Boveri, Driesch, and Herbst allowed conceptualization of basic biological themes, such as the chromosome theory of heredity.2 In the first half of the twentieth century, the embryo manipulation experiments performed by Hörstadius and Runnström further advanced the field, introducing the concept of morphogens double gradient.3 Later on, with the flowering of molecular biology and the advent of new technologies, scientists of the caliber of Hultin, Monroy, and Davidson emphasized that this echinoderm also represents an excellent model for studying the molecular basis of embryogenesis. 2 In the post-genomic era, the sea urchin embryo continued to be an unsurpassed model for determining the molecular mechanisms responsible for creating a multicellular organism, mainly because of its relative inexpensiveness, optical transparency, rapid synchronous development, and amenability to perform a powerful arsenal of experimental procedures.4 Although nowadays the carrying capacity is much lower than in years past, the sea urchin embryo is still a convenient model to study gene regulatory networks,5 response to environmental stressors,6 biomineralization,7 stem cell properties,8 and cancer.9 Undoubtedly, the breath of all this research makes it clear that the sea urchin embryo could help further generations of investigators to reveal the unsolved mysteries of life. 1. Ernst SG. Am Zool 1997;37:250-9. 2. Ernst SG. Dev Biol 2011;358:285-94. 3. Runnström J. Springer 1975;646-70. 4. Ettensohn CA et al. Methods Cell Biol 2004;vol 74. 5. Peter I and Davidson EH. 2015;Academic press. 6. Matranga V et al. Prog Mol Subcell Biol 2005;Springer. 7. Adomako-Ankomah A and Ettensohn CA. Genesis 2014;52:158-72. 8. Wessel GM. Curr Top Dev Biol 2016;117:553-66. 9. Saunders LR and McClay DR. Development 2014;141:1503-13.