Flowering plant sperm contains a cytosolic soluble protein factor which can trigger calcium oscillations in mouse eggs.
There is evidence showing that the sperm-induced Ca(2+) oscillations in mammalian eggs at fertilization are triggered by a sperm-derived protein factor. It was established recently that the activity of the putative sperm protein in causing Ca(2+) oscillations in mammalian eggs is not species-specific in vertebrates (1, 16). Here we report that cytosolic soluble extracts derived from flowering plant sperms in Brassica campestris can also induce fertilization-like Ca(2+) oscillations when microinjected into mouse eggs. The factor responsible for inducing Ca(2+) oscillations in the plant sperm was sperm-specific and heat- or trypsin-labile. Eight to ten sperm equivalents of the plant sperm extracts had enough activity to trigger Ca(2+) oscillations in mouse eggs. Our study suggests that, although plant and mammal are evolutionary divergent species, the activity of the putative sperm protein factor in triggering Ca(2+) signaling in mammalian eggs is not specific to the animal kingdom.
Li
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ST
Laboratory of Molecular Developmental Biology, Chinese Academy of Sciences, Beijing 100080, People's Republic of China.
Huang
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XY
Sun
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FZ
D000818:Animals; D001937:Brassica / Q000737:chemistry*; D020013:Calcium Signaling / Q000187:drug effects*; D003600:Cytosol / Q000378:metabolism; D005260:Female; D005306:Fertilization / Q000187:drug effects / Q000502:physiology; D008297:Male; D051379:Mice; D008813:Mice, Inbred ICR; D008845:Microinjections; D010063:Ovum / Q000187:drug effects* / Q000378:metabolism; D010940:Plant Proteins / Q000494:pharmacology*; D013094:Spermatozoa / Q000737:chemistry*
D010940:Plant Proteins