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. Author manuscript; available in PMC: 2011 Mar 1.
Published in final edited form as: Nat Chem Biol. 2010 Aug 8;6(9):674–681. doi: 10.1038/nchembio.419

Figure 5. Zinc-insufficient eggs can undergo a true fertilization event but display a delayed pronuclear stage and abnormal calcium oscillations upon activation.

Figure 5

Fertilized control (a) and zinc-insufficient (b) eggs were fixed 8 hpf for 5-methylcytidine staining. In both groups, one of the two pronuclei displayed an absence of signal (dotted circles), indicating demethylation and a male origin of the genetic material. However, embryos derived from zinc-insufficient oocytes experience a delayed pronuclear stage (c). At 24 hpf, when embryos from control eggs have proceeded to the two-cell stage, embryos from zinc-insufficient eggs still display two pronuclei. Upon activation, control eggs initiate a prolonged first calcium transient (d, arrow) followed by a regular series of shorter transients. Zinc-insufficient oocytes lack a large first transient and undergo a fewer total number of transients within the same imaging period. PB = polar body, scale bar = 25 μm.