TISSUE-SPECIFIC AND SPECIES-SPECIFIC EXPRESSION OF SP56, A MOUSE SPERM FERTILIZATION PROTEIN

Mouse sperm recognize and bind to ZP3, one of three glycoproteins in t he egg's zona pellucida. A mouse sperm protein, sp56, was identified t hat has the characteristics expected of the sperm protein responsible for recognition of ZP3. The complementary DNA encoding sp56 was isolat ed, and its primary sequence indicates that sp56 is a member of a supe rfamily of protein receptors. It was shown that sp56 expression is res tricted to mouse spermatids and that the presence or absence of sp56 o n sperm from different species accounts for species specificity of spe rm-egg recognition in mice.