Phospholipase C zeta undergoes dynamic changes in its pattern of localization in sperm during capacitation and the acrosome reaction

Objective

To evaluate the localization of phospholipase Cζ (PLCζ) in non-capacitated, capacitated, and ionophore-treated sperm.

Design

Phospholipase Cζ was cloned from the hamster, an important model organism for studying fertilization. Next, we used hamster and mouse models to investigate the localization of PLCζ in non-capacitated and capacitated sperm and in sperm treated with ionophore to induce the acrosome reaction.

Setting

University laboratory.

Animal(s)

Male mice and hamsters, 4–6 weeks old.

Intervention(s)

None.

Main Outcome Measure(s)

Phospholipase Cζ localization in non-capacitated, capacitated, and ionophore-treated sperm.

Result(s)

Full-length hamster PLCζ complementary DNA is 1953 base pairs in size, encoding an open reading frame of 651 amino acids, sharing 85% amino acid similarity with the mouse. Phospholipase Cζ was localized in acrosomal and post-acrosomal regions of sperm. The post-acrosomal localization, which became more evident after capacitation and was maintained after ionophore treatment, is in line with PLCζ being the endogenous agent of egg activation. However, the acrosomal PLCζ population, which was lost after ionophore treatment, suggests that PLCζ could have other functions besides egg activation.

Conclusion(s)

Phospholipase Cζ is localized to acrosomal and post-acrosomal regions and undergoes dynamic changes during capacitation and the acrosome reaction, indicating a potential role regulating not only egg activation but other sperm functions.

Key Words: Fertilization, egg activation, phospholipase C zeta, sperm, capacitation, acrosome reaction, hamster PLC zeta, molecular cloning