Search

Summary While it is appreciated that reactive oxygen species (ROS) can act as second messengers in both homeostastic and stress response signaling pathways, potential roles for ROS during early vertebrate development have remained largely unexplored. Here, we show that fertilization in Xenopus embryos triggers a rapid increase in ROS levels, which oscillate with each cell division. Furthermore, we show that the fertilization-induced Ca2+ wave is necessary and sufficient to induce ROS production in activated or fertilized eggs. Using chemical inhibitors, we identified mitochondria as the major source of fertilization-induced ROS production. Inhibition of mitochondrial ROS production in early embryos results in cell-cycle arrest, in part, via ROS-dependent regulation of Cdc25C activity. This study reveals a role for oscillating ROS levels in early cell cycle regulation in Xenopus embryos., Graphical Abstract, Highlights • ROS, including hydrogen peroxide, are produced after fertilization in Xenopus • Ca2+ signaling after fertilization induces ROS production in mitochondria • Mitochondria are the major source of oscillating ROS levels • ROS regulate Cdc25C activity and the early cell cycle, Han et al. show that the fertilization-triggered calcium wave induces reactive oxygen species production from mitochondria, which oscillate with each cell division in Xenopus embryos. Moreover, they demonstrate that inhibition of mitochondrial ROS production disrupts cell cycle progression.

For the past 50 years, the Xenopus amphibian model has been a cornerstone of biomedical research. Studies using this model have lead to many groundbreaking discoveries in areas as diverse as vertebrate embryology, cell and molecular biology, physiology, neurobiology, and endocrinology. These insights have paved the way for important applications across modern medicine. The tremendous impact of Xenopus in the research arena is afforded by a combination of its unique advantages, including large, robust, abundant eggs and embryos, its cost effectiveness, and its close evolutionary relationship to mammals, including humans. Looking forward, Xenopus will continue to be a powerful model system in biomedical research, as many of the latest state-of-the-art techniques are perfectly suited to the system. This chapter is intended to provide an overview for the clinician embarking on research using Xenopus. It is geared toward demonstrating its strengths as an adaptable, multifunctional model for studying human disease mechanisms.