Ca²⁺ dynamics in zebrafish morphogenesis

Intracellular calcium ion (Ca²⁺) signaling is heavily involved in development, as illustrated by the use of a number of Ca²⁺ indicators. However, continuous Ca²⁺ patterns during morphogenesis have not yet been studied using fluorescence resonance energy transfer to track the Ca²⁺ sensor. In the present study, we monitored Ca²⁺ levels during zebrafish morphogenesis and differentiation with yellow cameleon, YC2.12. Our results show not only clear changes in Ca²⁺ levels but also continuous Ca²⁺ patterns at 24 hpf and later periods for the first time. Serial Ca²⁺dynamics during early pharyngula period (Prim-5-20; 24-33 hpf) was successfully observed with cameleon, which have not reported anywhere yet. In fact, high Ca²⁺ level occurred concurrently with hindbrain development in segmentation and pharyngula periods. Ca²⁺ patterns in the late gastrula through segmentation periods which were obtained with cameleon, were similar to those obtained previously with other Ca²⁺sensor. Our results suggested that the use of various Ca²⁺ sensors may lead to novel findings in studies of Ca²⁺ dynamics. We hope that these results will prove valuable for further research in Ca²⁺ signaling.