The soluble sperm factor that causes Ca2+ release from sea-urchin (Lytechinus pictus) egg homogenates also triggers Ca2+ oscillations after injection into mouse eggs

Cytosolic extracts of boar sperm contain a soluble phospholipase C (PLC) activity that induces Ca²⁺ release in sea-urchin (Lytechinus pictus) egg homogenates and an uncharacterized protein factor that causes Ca²⁺ oscillations when injected into mammalian eggs. In the present study we fractionated boar sperm extracts on three different FPLC chromatographic columns and found that the fractions that caused maximal Ca²⁺ release in sea-urchin egg homogenates were also the ones that triggered Ca²⁺ oscillations in mouse eggs. Our data suggests that the sperm factor which triggers Ca²⁺ oscillations in eggs contains a PLC and not the 33 kDa glucosamine deaminase previously suggested to be one its components.