title: Role of ubiquitin C-terminal hydrolase-L1 in antipolyspermy defense of mammalian oocytes.
abstract: The ubiquitin-proteasome system regulates many cellular processes through rapid proteasomal degradation of ubiquitin-tagged proteins. Ubiquitin C-terminal hydrolase-L1 (UCHL1) is one of the most abundant proteins in mammalian oocytes. It has weak hydrolytic activity as a monomer and acts as a ubiquitin ligase in its dimeric or oligomeric form. Recently published data show that insufficiency in UCHL1 activity coincides with polyspermic fertilization; however, the mechanism by which UCHL1 contributes to this process remains unclear. Using UCHL1-specific inhibitors, we induced a high rate of polyspermy in bovine zygotes after in vitro fertilization. We also detected decreased levels in the monomeric ubiquitin and polyubiquitin pool. The presence of UCHL1 inhibitors in maturation medium enhanced formation of presumptive UCHL1 oligomers and subsequently increased abundance of K63-linked polyubiquitin chains in oocytes. We analyzed the dynamics of cortical granules (CGs) in UCHL1-inhibited oocytes; both migration of CGs toward the cortex during oocyte maturation and fertilization-induced extrusion of CGs were impaired. These alterations in CG dynamics coincided with high polyspermy incidence in in vitro-produced UCHL1-inhibited zygotes. These data indicate that antipolyspermy defense in bovine oocytes may rely on UCHL1-controlled functioning of CGs.
authors.affiliation: Institute of Animal Physiology and Genetics, Academy of Sciences of the Czech Republic, Libechov, Czech Republic. susor@iapg.cas.cz
authors.forename: Andrej
authors.initials: A
authors.lastname: Susor
authors.forename: Lucie
authors.initials: L
authors.lastname: Liskova
authors.forename: Tereza
authors.initials: T
authors.lastname: Toralova
authors.forename: Antonin
authors.initials: A
authors.lastname: Pavlok
authors.forename: Katerina
authors.initials: K
authors.lastname: Pivonkova
authors.forename: Pavla
authors.initials: P
authors.lastname: Karabinova
authors.forename: Miloslava
authors.initials: M
authors.lastname: Lopatarova
authors.forename: Peter
authors.initials: P
authors.lastname: Sutovsky
authors.forename: Michal
authors.initials: M
authors.lastname: Kubelka
mesh_terms: D000818:Animals; D002417:Cattle; D005260:Female; D005306:Fertilization; D005307:Fertilization in Vitro; D009865:Oocytes / Q000201:enzymology*; D025821:Polyubiquitin / Q000032:analysis; D025822:Ubiquitin C / Q000032:analysis; D043222:Ubiquitin Thiolesterase / Q000037:antagonists & inhibitors / Q000378:metabolism*; D015053:Zygote / Q000201:enzymology
chemical_list: D025822:Ubiquitin C; D025821:Polyubiquitin; D043222:Ubiquitin Thiolesterase