title: Loss of cysteine-rich secretory protein 4 (Crisp4) leads to deficiency in sperm-zona pellucida interaction in mice.
abstract: Mammalian sperm gain their ability to fertilize the egg during transit through the epididymis and by interacting with proteins secreted by the epididymal epithelial cells. Certain members of the CRISP (cysteine-rich secretory protein) family form the major protein constituent of the luminal fluid in the mammalian epididymis. CRISP4 is the newest member of the CRISP family expressed predominantly in the epididymis. Its structure and expression pattern suggest a role in sperm maturation and/or sperm-egg interaction. To study the relevance of CRISP4 in reproduction, we have generated a Crisp4 iCre knock-in mouse model through insertion of the iCre recombinase coding cDNA into the Crisp4 locus. This allows using the mouse line both as a Crisp4 deficient model and as an epididymis-specific iCre-expressing mouse line applicable for the generation of conditional, epididymis-specific knockout mice. We show that the loss of CRISP4 leads to a deficiency of the spermatozoa to undergo progesterone-induced acrosome reaction and to a decreased fertilizing ability of the sperm in the in vitro fertilization conditions, although the mice remain fully fertile in normal mating. However, removal of the egg zona pellucida returned the fertilization potential of the CRISP4-deficient spermatozoa, and accordingly we detected a reduced number of Crisp4-deficient spermatozoa bound to oocytes as compared with the wild-type spermatozoa. We also demonstrate that iCre recombinase is expressed in a pattern similar to endogenous Crisp4 and is able to initiate the recombination event with its target sequences in vivo.
authors.affiliation: Department of Physiology, Institute of Biomedicine, University of Turku, Finland.
authors.forename: Heikki T
authors.initials: HT
authors.lastname: Turunen
authors.forename: Petra
authors.initials: P
authors.lastname: Sipilä
authors.forename: Anton
authors.initials: A
authors.lastname: Krutskikh
authors.forename: Jussi
authors.initials: J
authors.lastname: Toivanen
authors.forename: Harri
authors.initials: H
authors.lastname: Mankonen
authors.forename: Veera
authors.initials: V
authors.lastname: Hämäläinen
authors.forename: Ida
authors.initials: I
authors.lastname: Björkgren
authors.forename: Ilpo
authors.initials: I
authors.lastname: Huhtaniemi
authors.forename: Matti
authors.initials: M
authors.lastname: Poutanen
mesh_terms: D000818:Animals; D005260:Female; D005298:Fertility; D005307:Fertilization in Vitro; D005786:Gene Expression Regulation / Q000502:physiology; D019426:Integrases / Q000235:genetics / Q000378:metabolism; D008297:Male; D051379:Mice; D018345:Mice, Knockout; D008822:Mice, Transgenic; D029589:Seminal Plasma Proteins / Q000235:genetics / Q000378:metabolism*; D013084:Sperm-Ovum Interactions / Q000502:physiology*; D013094:Spermatozoa / Q000502:physiology*; D015044:Zona Pellucida / Q000502:physiology*
chemical_list: D029589:Seminal Plasma Proteins; C503718:cysteine-rich secretory protein 4, mouse; C045073:Cre recombinase; D019426:Integrases