Understanding the molecular and cellular processes that underpin animal development are crucial for understanding the diversity of body plans found on the planet today. Because of their abundance in the fossil record, and tractability as a model system in the lab, skeletons provide an ideal experimental model to understand the origins of animal diversity. We herein use molecular and cellular markers to understand the growth and development of the juvenile sea urchin (echinoid) skeleton. We developed a detailed staging scheme based off of the first ~four weeks of post-metamorphic life of the regular echinoid Paracentrotus lividus. We paired this scheme with immunohistochemical staining for neuronal, muscular, and skeletal tissues, and fluorescent assays of skeletal growth and cell proliferation to understand the molecular and cellular mechanisms underlying skeletal growth and development of the sea urchin body plan. Our experiments highlight the role of skeletogenic proteins in accretionary skeletal growth and cell proliferation in the addition of new metameric tissues. Furthermore, our work provides a framework for understanding the developmental evolution of sea urchin body plans on macroevolutionary timescales.

中文翻译：

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海胆Paracentrotus lividus的变质后骨骼生长及其对人体计划演变的影响

了解支撑动物发育的分子和细胞过程对于理解当今星球上人体计划的多样性至关重要。由于其在化石记录中的丰富性以及作为实验室中模型系统的易处理性，骨骼为了解动物多样性的起源提供了理想的实验模型。我们在本文中使用分子和细胞标记物来了解少年海胆（类骨质）骨架的生长和发育。我们根据常规类棘突类动物拟蝶虫的变态后生命的前约四周制定了详细的分期方案。我们将该方案与针对神经元，肌肉和骨骼组织的免疫组织化学染色以及骨骼生长和细胞增殖的荧光分析相结合，以了解海胆人体计划的骨骼生长和发育的分子和细胞机制。我们的实验着重于添加新的同聚异体组织时，促骨骼蛋白在增生性骨骼生长和细胞增殖中的作用。此外，我们的工作提供了一个框架，可用于在宏观进化时间尺度上理解海胆人体计划的发展演变。