The long term objective is to determine the molecular alterations that produce ultrastructural and fertilization related functional changes in egg envelopes. Structural changes in the glycoproteins composing the egg envelope will be correlated with functional changes in sperm binding, induction of the sperm acrosome reaction, and sperm penetration of the envelope. The animal being used is the frog Xenopus laevis.
Specific aims i nclude structure-function studies of the coelomic to vitelline envelope conversion which takes place in the pars recta oviduct and the vitelline envelope to fertilization envelope conversion which occurs at fertilization. A pars recta protease responsible for the coelomic to vitelline envelope conversion will be isolated and characterized as a protein and an enzyme. The gene for this protease will be cloned using recombinant DNA methodology to assist in determining protein structure. The chemical action of the enzyme on its glycoprotein envelope substrate will be determined by comparing the primary structure of the 43K substrate and the 41K product. Alteration of the sperm binding properties caused by limited hydrolysis will be investigated. At fertilization, the vitelline envelope is modified by the addition of a fertilization (F) layer and limited hydrolysis of 69K and 64K envelope glycoproteins. The F layer is produced by a cortical granule lectinprefertilization layer ligand reaction. We will determine the primary structure of the glycoprotein lectin and isolate and structurally characterize its ligand. Recombinant DNA methodology will be used to assist in determining protein structure. The ligand will be analyzed for its acrosome reaction inducing activity to test the hypothesis that formation of the F layer blocks sperm penetration because lectin binding inhibits the acrosome reaction inducing activity of the ligand. Evidence will be sought for a role of the 69K, 64K glycoproteins in binding the F layer to the envelope. These structure function studies will increase our understanding of the role of these molecules in fertilization and also our fundamental knowledge of lectin-ligand interactions.

Agency
National Institute of Health (NIH)
Institute
Eunice Kennedy Shriver National Institute of Child Health & Human Development (NICHD)
Type
Research Project (R01)
Project #
5R01HD004906-21
Application #
3310340
Study Section
Reproductive Biology Study Section (REB)
Project Start
1975-05-01
Project End
1993-04-30
Budget Start
1990-05-01
Budget End
1991-04-30
Support Year
21
Fiscal Year
1990
Total Cost
Indirect Cost
Name
University of California Davis
Department
Type
Schools of Earth Sciences/Natur
DUNS #
094878337
City
Davis
State
CA
Country
United States
Zip Code
95618
Chang, Betty Y; Peavy, Thomas R; Wardrip, Nathan J et al. (2004) The Xenopus laevis cortical granule lectin: cDNA cloning, developmental expression, and identification of the eglectin family of lectins. Comp Biochem Physiol A Mol Integr Physiol 137:115-29
Lindsay, L L; Wieduwilt, M J; Hedrick, J L (1999) Oviductin, the Xenopus laevis oviductal protease that processes egg envelope glycoprotein gp43, increases sperm binding to envelopes, and is translated as part of an unusual mosaic protein composed of two protease and several CUB domains. Biol Reprod 60:989-95
Lindsay, L L; Yang, J C; Hedrick, J L (1999) Ovochymase, a Xenopus laevis egg extracellular protease, is translated as part of an unusual polyprotease. Proc Natl Acad Sci U S A 96:11253-8
Yang, J C; Hedrick, J L (1997) cDNA cloning and sequence analysis of the Xenopus laevis egg envelope glycoprotein gp43. Dev Growth Differ 39:457-67
Hedrick, J L (1996) Comparative structural and antigenic properties of zona pellucida glycoproteins. J Reprod Fertil Suppl 50:9-17
Quill, T A; Hedrick, J L (1996) The fertilization layer mediated block to polyspermy in Xenopus laevis: isolation of the cortical granule lectin ligand. Arch Biochem Biophys 333:326-32
Lindsay, L L; Hedrick, J L (1995) Isolation and characterization of ovochymase, a chymotrypsin-like protease released during Xenopus laevis egg activation. Dev Biol 167:513-6
Hardy, D M; Hedrick, J L (1992) Oviductin. Purification and properties of the oviductal protease that processes the molecular weight 43,000 glycoprotein of the Xenopus laevis egg envelope. Biochemistry 31:4466-72
Lindsay, L L; Larabell, C A; Hedrick, J L (1992) Localization of a chymotrypsin-like protease to the perivitelline space of Xenopus laevis eggs. Dev Biol 154:433-6
Hedrick, J L; Hardy, D M (1991) Isolation of extracellular matrix structures from Xenopus laevis oocytes, eggs, and embryos. Methods Cell Biol 36:231-47

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