Molecular insights into the divergence and diversity of post-testicular maturation strategies

A novel role for milk fat globule‐EGF factor 8 protein (MFGE8) in the mediation of mouse sperm–extracellular vesicle interactions

“…There is mounting evidence that epididymosomes play a fundamental role in promoting sperm function via the exchange of fertility modulating proteins and epigenetic cargo [3]. Nevertheless, the mechanisms F I G U R E 5 5Characterization of the role of MFGE8 -integrin αV in sperm-extracellular vesicle interactions.…”

“…There is mounting evidence that epididymosomes play a fundamental role in promoting sperm function via the exchange of fertility modulating proteins and epigenetic cargo [3]. Nevertheless, the mechanisms that facilitate the selective adhesion and subsequent uptake of the epididymosome payload into recipient spermatozoa have yet to be fully resolved.…”

“…In the case of the spermatozoon, this journey to maturity is initiated within the testes during which time the germline undergoes sequential mitotic and meiotic divisions followed by cytoplasmic and nuclear remodeling to eventually give rise to one of the most highly differentiated cells in the mammalian body [2]. Notwithstanding this morphological transformation, mammalian sperm cells only acquire the acumen to fertilize an ovum during their carriage through the epididymal portion of the male extragonadal duct system [3]. This conversion into fertilization competent cells is accompanied by substantive modification of the sperm proteomic [4] and epigenetic landscapes [5]; processes that occur in the complete absence of nuclear gene transcription and protein translation.…”

A possible highway system for the rapid delivery of sperm from the testis to the penis in the naked mole‐rat, Heterocephalus glaber

“…The level of sperm competition has been associated with relative testis and accessory gland size, as well as sperm quantity, morphology and functionality in various taxa (Boschetto et al, 2011; Byrne et al, 2003; Gomendio & Roldan, 2008; Lüpold et al, 2009; Montoto et al, 2011; Parker, 1990; Ramm et al, 2005; van der Horst & Maree, 2014). In spite of this rich niche of publications, surprisingly little focus has been placed on the relationship between sperm competition level and post‐testicular sperm transport, maturation and storage, especially in mammals (Nixon et al, 2020). Our study has addressed this void by discussing the possible effect of the absence of sperm competition on the detailed structure of the NMR reproductive tract.…”

“…The epididymis is divided into the caput, corpus, and cauda epididymides, contains more than six histological zones and can be several meters long due to excessive coiling of the duct (Cleland & Reid, 1957; Hermo & Robaire, 2002; van der Horst, 1972). While in some vertebrate species the extra‐testicular ducts are mainly conduits for sperm transport, the eutherian reproductive tract has many specializations for sperm maturation and storage (Cornwall, 2009; Jones, 2002; Nixon et al, 2020). Mainly two types of vesicles from merocrine and apocrine origins have been observed in the excurrent ducts of many mammalian species and there has been an ongoing debate about their functional role in sperm maturation (Hermo & Jacks, 2002; Sharma et al, 2016; Sullivan & Saez, 2013).…”