title: Sperm proteasome degrades egg envelope glycoprotein ZP1 during fertilization of Japanese quail (Coturnix japonica).
abstract: At the time of fertilization, the extracellular matrix surrounding avian oocytes, termed the perivitelline membrane (pvm), is hydrolyzed by a sperm-borne protease, although the actual protease that is responsible for the digestion of the pvm remains to be identified. Here, we show evidence that the ubiquitin-proteasome system is functional in the fertilization of Japanese quail. The activities for the induction of the acrosome reaction and binding to ZP3 as revealed by ligand blotting of purified serum ZP1 are similar to those of pvm ZP1. Western blot analysis of purified ZP1 and ZP3 by the use of the anti-ubiquitin antibody showed that only pvm ZP1 was reactive to the antibody. In vitro penetration assay of the sperm on the pvm indicated that fragments of ZP1 and intact ZP3 were released from the pvm. Western blot analysis using the anti-20S proteasome antibody and ultrastructural analysis showed that immunoreactive proteasome was localized in the acrosomal region of the sperm. Inclusion of specific proteasome inhibitor MG132 in the incubation mixture, or depletion of extracellular ATP by the addition of apyrase, efficiently suppressed the sperm perforation of the pvm. These results demonstrate for the first time that the sperm proteasome is important for fertilization in birds and that the extracellular ubiquitination of ZP1 might occur during its transport via blood circulation.
authors.affiliation: Department of Applied Biological Chemistry, Faculty of Agriculture, Shizuoka University, 836 Ohya, Shizuoka 422-8529, Japan. atsasan@ipc.shizuoka.ac.jp
authors.forename: Tomohiro
authors.initials: T
authors.lastname: Sasanami
authors.forename: Kenichi
authors.initials: K
authors.lastname: Sugiura
authors.forename: Toshinobu
authors.initials: T
authors.lastname: Tokumoto
authors.forename: Norio
authors.initials: N
authors.lastname: Yoshizaki
authors.forename: Hideo
authors.initials: H
authors.lastname: Dohra
authors.forename: Shunsuke
authors.initials: S
authors.lastname: Nishio
authors.forename: Shusei
authors.initials: S
authors.lastname: Mizushima
authors.forename: Gen
authors.initials: G
authors.lastname: Hiyama
authors.forename: Tsukasa
authors.initials: T
authors.lastname: Matsuda
mesh_terms: D000177:Acrosome / Q000187:drug effects / Q000378:metabolism / Q000648:ultrastructure; D020101:Acrosome Reaction / Q000187:drug effects; D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D030161:Avian Proteins / Q000037:antagonists & inhibitors / Q000097:blood / Q000737:chemistry / Q000378:metabolism*; D001692:Biological Transport; D003370:Coturnix / Q000502:physiology*; D004527:Egg Proteins / Q000097:blood / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D005260:Female; D005306:Fertilization / Q000187:drug effects; D008297:Male; D008562:Membrane Glycoproteins / Q000097:blood / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D016253:Microscopy, Immunoelectron; D010446:Peptide Fragments / Q000737:chemistry / Q000378:metabolism; D046988:Proteasome Endopeptidase Complex / Q000378:metabolism*; D061988:Proteasome Inhibitors / Q000494:pharmacology; D020033:Protein Isoforms / Q000097:blood / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism; D011956:Receptors, Cell Surface / Q000097:blood / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D013094:Spermatozoa / Q000201:enzymology / Q000378:metabolism* / Q000648:ultrastructure; D054875:Ubiquitination; D015044:Zona Pellucida / Q000378:metabolism*; D000072216:Zona Pellucida Glycoproteins
chemical_list: D030161:Avian Proteins; D004527:Egg Proteins; D008562:Membrane Glycoproteins; D010446:Peptide Fragments; D061988:Proteasome Inhibitors; D020033:Protein Isoforms; D011956:Receptors, Cell Surface; D000072216:Zona Pellucida Glycoproteins; D000255:Adenosine Triphosphate; D046988:Proteasome Endopeptidase Complex