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. Author manuscript; available in PMC: 2015 Aug 1.
Published in final edited form as: Nat Chem. 2014 Dec 15;7(2):130–139. doi: 10.1038/nchem.2133

Figure 5. Live cell fluorescence zinc imaging demonstrates intracellular zinc compartments are the source of the extracellular zinc spark.

Figure 5

MII eggs labeled with 50 nM ZincBY-1 (intracellular, green) were activated with 10 mM SrCl2 in medium containing 50 µM FluoZin-3 (extracellular, red). All scale bars = 20 µm.

(a–c) Whole egg was imaged in a z-stack time course (5 µm optical sections taken over 6.5 seconds).

(a) Z-stack projections of ZincBY-1 and FluoZin-3 fluorescence during a zinc spark. Arrows indicate concentrated regions of zinc exocytosis.

(b) Overlaid optical sections of pre-spark ZincBY-1 fluorescence and FluoZin-3 fluorescence during a zinc spark. Z-stack position is indicated in each panel.

(c) Angular analysis of intracellular and extracellular fluorescence distribution in a z-section (z14 shown, others in SI). Fluorescence intensity pattern is the same in both channels, indicating that zinc-enriched vesicles are the source of the zinc spark.

(d–e) Egg imaged in a 1 µm confocal section.

(d) Images from time course taken before (i), during (ii), and after (iii) a zinc spark. Brightfield image indicates intracellular and extracellular ROIs.

(e) Time traces show simultaneous decrease in intracellular fluorescence and increase in extracellular fluorescence, indicating that zinc-enriched vesicles are the source of the zinc spark.