Elucidating the Role of the Epididymis in Conception by Targeted Gene Inactivation

Abstract

It is now well established that spermatozoa of eutherian mammals are continuously released from the seminiferous epithelium as infertile and virtually immotile gametes, that they undergo further maturation in the proximal epididymis, and that large numbers of them are subsequently stored in a quiescent state in the distal portion of the Wolffian duct until ejaculated. However, there remains a considerable lack of understanding as to the nature of sperm/epididymis relationship, nor is there any certainty about the biological significance ofthis organ. The thesis describes an attempt to address these questions in the mouse by applying the methods ofreverse genetics. . Given the potential of the CrelloxP binary transgenic technology, an attempt was made to produce a panel oftransgenic mice with regionalized Cre-recombinase expression under the transcriptional control ofthe epididymis-specific genes: RnaselO, EG627821, Crispl, Crisp4 and Dejb41. Using the knock-in approach, RnaselOCre (initial segment) and Crisp4cre (zones 2-4) mouse lines were derived. Since the initial segment is the primary site of sperm maturation, and the ~ epididymal epithelium is reliant on androgenic support, an initial segment-specific androgen receptor Ar) knock-out was generated by intercrossing the Rnase1OCre mouse with an A/oxP mouse. Consequences of this manipulation are described, as is the phenotype ofthe RnaselOCre/Cre(-/-) male. The findings challenge the reductionist model offertilization in the mouse, and the place of the epididymis in the chain of eutherian conception is discussed.EThOS - Electronic Theses Online ServiceGBUnited Kingdo