Transmembrane fluxes of Ca²⁺ and H⁺ are crucial for early development in vertebrates. In amphibians such as Xenopus laevis, transmembrane fluxes of Ca²⁺ and H⁺ are known to be involved in regulating neural induction. It has previously been shown that starting from the late blastula stage of Xenopus development, induction of the dorsal ectoderm by the dorsal mesoderm results in transmembrane Ca²⁺ and H⁺ fluxes in the dorsal animal hemisphere. These ion fluxes cause intracellular Ca²⁺ signaling events and intracellular alkalinization, which subsequently activate proneural genes. However, the molecular mechanisms regulating the ion fluxes is still unclear. It has been suggested that transient receptor potential channel 1 (TRPC1) might play a role in the generation of the Ca²⁺ influx...[ Read more ]

Transmembrane fluxes of Ca²⁺ and H⁺ are crucial for early development in vertebrates. In amphibians such as Xenopus laevis, transmembrane fluxes of Ca²⁺ and H⁺ are known to be involved in regulating neural induction. It has previously been shown that starting from the late blastula stage of Xenopus development, induction of the dorsal ectoderm by the dorsal mesoderm results in transmembrane Ca²⁺ and H⁺ fluxes in the dorsal animal hemisphere. These ion fluxes cause intracellular Ca²⁺ signaling events and intracellular alkalinization, which subsequently activate proneural genes. However, the molecular mechanisms regulating the ion fluxes is still unclear. It has been suggested that transient receptor potential channel 1 (TRPC1) might play a role in the generation of the Ca²⁺ influx, and the activity of the vacuolar H⁺-ATPase (V-ATPase) might be involved in generating the H⁺ efflux. Here, I present new data, which indicate the presence and function of TRPC1 during neural induction in the dorsal ectoderm. Furthermore, using the non-invasive scanning ion-selective electrode technique (SIET), I demonstrated the presence of an extracellular H⁺ efflux located near to the surface of the dorsal animal hemisphere. In addition, I established the capability of the luminescent transgenic CMV-GFP-apoaequorin X. tropicalis and NBT-GFP-apoaequorin X. laevis as models for studying Ca²⁺ signaling during neural induction.