Visualizing zinc dynamics in cell division and developing zebrafish
Bourassa, Daisy M.
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Despite the importance of zinc in cell proliferation and development, mechanisms of zinc redistribution during these processes remain largely elusive. Given the limited external supply of nutrients during embryogenesis, developing organs most likely redistribute zinc from neighboring cells to satisfy their increased demand, thus raising the intriguing and fundamental question of how the limited supply of zinc in a fertilized egg is redistributed in the course of embryonic development. To systematically explore this question, we employed both cell culture and zebrafish as model systems in combination with a Zn(II)-selective fluorescent probe and synchrotron X-ray fluorescence (SXRF) microtomography studies. Using the Zn(II)-selective emission ratiometric fluorescent probe designed in our lab, we followed the redistribution dynamics of labile Zn(II) pools in a zebrafish embryo during the first 24 hours post fertilization. Furthermore, SXRF microtomography studies were used to visualize the 3D distribution of total zinc in fixed zebrafish samples. From this method we successfully reconstructed a 3D elemental distribution map at 5 μm resolution. The volumetric map revealed a distinct zinc distribution that could be correlated with characteristic anatomical features at this stage of embryonic development. Together these powerful techniques allow us to study both labile zinc in live samples and total zinc content in fixed samples in order to achieve a more detailed understanding of the zinc redistribution dynamics during embryogenesis.