title: Conservation of sequence and function in fertilization of the cortical granule serine protease in echinoderms.
abstract: Conservation of the cortical granule serine protease during fertilization in echinoderms was tested both functionally in sea stars, and computationally throughout the echinoderm phylum. We find that the inhibitor of serine protease (soybean trypsin inhibitor) effectively blocks proper transition of the sea star fertilization envelope into a protective sperm repellent, whereas inhibitors of the other main types of proteases had no effect. Scanning the transcriptomes of 15 different echinoderm ovaries revealed sequences of high conservation to the originally identified sea urchin cortical serine protease, CGSP1. These conserved sequences contained the catalytic triad necessary for enzymatic activity, and the tandemly repeated LDLr-like repeats. We conclude that the protease involved in the slow block to polyspermy is an essential and conserved element of fertilization in echinoderms, and may provide an important reagent for identification and testing of the cell surface proteins in eggs necessary for sperm binding.
authors.affiliation: Department of Molecular and Cell Biology and Biochemistry, Brown University, 185 Meeting St., Providence, RI 02912, USA.
authors.forename: Nathalie
authors.initials: N
authors.lastname: Oulhen
authors.affiliation: Department of Molecular and Cell Biology and Biochemistry, Brown University, 185 Meeting St., Providence, RI 02912, USA; Marine Fishery Institute of Zhejiang Province, Key Lab of Mariculture and Enhancement of Zhejiang Province, 316100 Zhoushan, Zhejiang Province, PR China.
authors.forename: Dongdong
authors.initials: D
authors.lastname: Xu
authors.affiliation: Department of Molecular and Cell Biology and Biochemistry, Brown University, 185 Meeting St., Providence, RI 02912, USA. Electronic address: rhet@brown.edu.
authors.forename: Gary M
authors.initials: GM
authors.lastname: Wessel
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D017124:Conserved Sequence; D004447:Echinodermata / Q000145:classification / Q000235:genetics / Q000502:physiology*; D005260:Female; D005306:Fertilization / Q000187:drug effects / Q000235:genetics / Q000502:physiology*; D008297:Male; D008969:Molecular Sequence Data; D010063:Ovum / Q000187:drug effects / Q000502:physiology; D010802:Phylogeny; D017386:Sequence Homology, Amino Acid; D057057:Serine Proteases / Q000235:genetics / Q000502:physiology*; D015842:Serine Proteinase Inhibitors / Q000494:pharmacology; D013084:Sperm-Ovum Interactions / Q000187:drug effects / Q000235:genetics / Q000502:physiology; D047270:Strongylocentrotus purpuratus / Q000187:drug effects / Q000235:genetics / Q000502:physiology; D059467:Transcriptome
chemical_list: D015842:Serine Proteinase Inhibitors; D057057:Serine Proteases
keywords: Cortical granule protease; Cortical granules; Echinoderms; Egg receptor for sperm; Fertilization; Sea star