Xenopus and Chicken Sperm Contain a Cytosolic Soluble Protein Factor Which Can Trigger Calcium Oscillations in Mouse Eggs

• DOI: 10.1006/bbrc.2000.2218
• Publication Date: 2002-10-07T00:07:46Z
• Authors: Jian-Bo Dong; Tie-Shan Tang; Fang-Zhen Sun
• Keywords: Male; Sperm-Ovum Interactions; 0301 basic medicine; 0303 health sciences; Microinjections; Proteins; In Vitro Techniques; Spermatozoa; Molecular Weight; Mice; Xenopus laevis; 03 medical and health sciences; Species Specificity; Fertilization; Animals; Cattle; Female; Calcium Signaling; Chickens; Ovum

There is evidence showing that at fertilization the sperm introduces into egg cytoplasm a protein-based cytosolic factor, which serves as the physiological trigger for inducing Ca(2+) oscillations in mammalian eggs. Here we show that sperm of nonmammalian vertebrates also contain a cytosolic protein factor that can induce Ca(2+) oscillations when introduced into mammalian eggs. We have observed that cytosolic extracts derived from Xenopus or chicken sperm could induce mouse eggs to undergo Ca(2+) oscillations similar to those induced by bovine sperm extracts. The factor responsible for inducing Ca(2+) oscillations was of high molecular weight and heat- or proteinase K-labile. We show that 0.5 chicken sperm-equivalents or 1-2 Xenopus sperm-equivalents of the extracts had enough activity to trigger Ca(2+) oscillations in mouse eggs. Our findings illustrate that although Xenopus, chicken, and mammals are evolutionarily divergent species, the function of the sperm protein factor in triggering Ca(2+) oscillations in mammalian eggs appears not to be species specific in vertebrates.