title: Degradation of an extracellular matrix: sea urchin hatching enzyme removes cortical granule-derived proteins from the fertilization envelope.
abstract: The sea urchin fertilization envelope is an extracellular matrix assembled at fertilization to prevent polyspermy and protect the embryo during early development. During hatching, the embryo secretes a proteolytic hatching enzyme which dissolves the fertilization envelope, allowing a ciliated blastula to swim free. In this study we examined ultrastructural changes in the fertilization envelope during degradation of this matrix by hatching enzyme. The completed fertilization envelope is a trilaminar structure consisting of a dense, central layer of filaments sandwiched between surface coats of paracrystalline material. Hatching enzyme disassembles this matrix by degrading the paracrystalline layers and removing macromolecules from the central layer leaving behind a thin matrix of loosely woven fibers.
authors.affiliation: Department of Zoology, Arizona State University, Tempe 85287-1501.
authors.forename: N M
authors.initials: NM
authors.lastname: Mozingo
authors.forename: L R
authors.initials: LR
authors.lastname: Hollar
authors.forename: D E
authors.initials: DE
authors.lastname: Chandler
mesh_terms: D000818:Animals; D046508:Culture Techniques; D004527:Egg Proteins / Q000378:metabolism*; D004625:Embryo, Nonmammalian / Q000201:enzymology* / Q000648:ultrastructure; D005109:Extracellular Matrix / Q000378:metabolism*; D005306:Fertilization / Q000502:physiology*; D008666:Metalloendopeptidases / Q000378:metabolism*; D008855:Microscopy, Electron, Scanning; D012617:Sea Urchins / Q000201:enzymology
chemical_list: D004527:Egg Proteins; D008666:Metalloendopeptidases; C024344:envelysin