Figure 4. PLCζ-induced [Ca²⁺]_i oscillations are unchanged with maternal age.

(a,b) Typical Ca²⁺ oscillatory pattern in young and naturally-aged eggs following microinjection with PLCζ cRNA. (c) Quantification of the number of Ca²⁺ spikes in two hours following the first oscillation in young (n = 31) and aged (n = 12) eggs showed that maternal age does not affect the eggs ability to respond to a PLCζ signal at fertilization (P = 0.97). (d) Quantification of the average oscillation amplitude in young (n = 31) and aged (n = 12) eggs showed no difference with age (P = 0.51). (e) Quadratic regression analysis of oscillation number and PLCζ protein expression level (measured as luminescence levels) in young (black) and aged (red) eggs revealed age does not affect the sensitivity of PLCζ-induced Ca²⁺ oscillations. R² values are 0.88 and 0.94 (P = 0.56) for young and aged eggs, respectively. Experiments performed in Ca²⁺ -containing media. F/F0 represents fluorescent intensity relative to baseline. cps represents counts per second. ns indicates not statistically significant. Error bars are s.e.m.