Loss of Cysteine-Rich Secretory Protein 4 (Crisp4) Leads to Deficiency in Sperm-Zona Pellucida Interaction in Mice1

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.

Sperm-associated antigen 11A is expressed exclusively in the principal cells of the mouse caput epididymis in an androgen-dependent manner

“…Moreover, mouse Spag11a exhibited a region-specific expression pattern and was mainly present in the caput region. This is similar to several genes that are important for sperm maturation such as Rnase10 [34,35], Crisp4 [36,37], and Crisp1 [17], which are exclusively expressed in the initial segment, caput and corpus/cauda, respectively. This region-specific expression is important to create specific environments for sperm maturation.…”

Partial Deletion of Chromosome 8 β-defensin Cluster Confers Sperm Dysfunction and Infertility in Male Mice

“…Paradoxically the sperm from the mutants are extremely poor at binding firmly to the ZP of eggs, whereas wild-type sperm bind effectively (Figure 4E). Recent studies in the mouse have shown that sperm that have undergone the AR can penetrate an egg, although this was not an efficient process [25], [26] and mouse sperm from several KOs cannot strongly bind to the ZP and yet are still able to fertilize [27], [28].…”

The Oviduct: Functional Genomic and Proteomic Approach

“…It has been reported that the female genital tract has a positive effect on the fertilization potential of spermatozoa that have been genetically altered (Kawano et al. 2010; Turunen et al. 2012).…”