Proteolysis of Xenopus laevis egg envelope ZPA triggers envelope hardening.
The egg envelope of most animal eggs is modified following fertilization, resulting in the prevention of polyspermy and hardening of the egg envelope. In frogs and mammals a prominent feature of envelope modification is N-terminal proteolysis of the envelope glycoprotein ZPA. We have purified the ZPA protease from Xenopus laevis eggs and characterized it as a zinc metalloprotease. Proteolysis of isolated egg envelopes by the isolated protease resulted in envelope hardening. The N-terminal peptide fragment of ZPA remained disulfide bond linked to the ZPA glycoprotein moiety following proteolysis. We propose a mechanism for egg envelope hardening involving ZPA proteolysis by an egg metalloprotease as a triggering event followed by induction of global conformational changes in egg envelope glycoproteins.
Department of Animal Science, University of California, Davis, CA 95616, United States. lllindsay@ucdavis.edu
Leann L
LL
Lindsay
Jerry L
JL
Hedrick
D000818:Animals; D000906:Antibodies / Q000737:chemistry; D015153:Blotting, Western; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000378:metabolism; D004527:Egg Proteins / Q000737:chemistry*; D004591:Electrophoresis, Polyacrylamide Gel; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005260:Female; D005306:Fertilization; D008297:Male; D008562:Membrane Glycoproteins / Q000737:chemistry*; D045726:Metalloproteases / Q000378:metabolism; D010063:Ovum / Q000378:metabolism; D010447:Peptide Hydrolases / Q000737:chemistry; D011480:Protease Inhibitors / Q000494:pharmacology; D017434:Protein Structure, Tertiary; D011506:Proteins / Q000737:chemistry; D011956:Receptors, Cell Surface / Q000737:chemistry*; D013094:Spermatozoa / Q000378:metabolism; D013696:Temperature; D014982:Xenopus laevis; D015044:Zona Pellucida / Q000737:chemistry* / Q000378:metabolism; D000072216:Zona Pellucida Glycoproteins
D000906:Antibodies; D018076:DNA, Complementary; D004527:Egg Proteins; D004791:Enzyme Inhibitors; D008562:Membrane Glycoproteins; D011480:Protease Inhibitors; D011506:Proteins; D011956:Receptors, Cell Surface; D000072216:Zona Pellucida Glycoproteins; D045726:Metalloproteases; D010447:Peptide Hydrolases