Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P56851 (epididymal)
 11,273 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Soluble antigens, specific for mouse testis, were detected by immunoelectrophoresis using a rabbit antiserum against a testicular extract (TE; supernatant of a mouse testicular homogenate spun at 105,000 g for 2 hr). At least 18 archs of precipitation were defined for the adult TE, but only three were testis specific. They were found in the epididymal extract, thus suggesting that these may be spermatozoal antigens. In immature mice, the testis-specific antigens start to appear in coincidence with the onset of pachytene spermatocytes. Immunohistochemical observations (peroxidase-antiperoxidase) showed specific reaction over spermatocytes and spermatids. The site of reaction was the surface or the peripheric cytoplasm of these cells.
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PMID:Testicular specific soluble antigens and spermatogenic onset in the mouse. 714 54

The periacrosomal plasma membrane of spermatozoa is involved in sperm binding to oviductal epithelial cells and to the zona pellucida. A protein of 68-70 kD molecular mass was purified biochemically from the isolated periacrosomal plasma membrane of equine spermatozoa as a possible receptor for adhesion of spermatozoa to oviductal epithelial cells. A polyclonal antibody raised in rabbits against the purified equine sperm membrane protein recognized the 70 kD and an antigenically related to 32 kD protein in preparations of isolated periacrosomal sperm plasma membrane and in detergent extracted ejaculated and epididymal spermatozoa. A larger protein (approximately 110 kD) was detected in equine testis. Two antigenically related proteins (64 and 45 kD) were recognized on the plasma membrane of cynomolgus macaque spermatozoa. In vitro sperm-binding assays were performed in the presence of antigen-binding fragments or IgG purified from the polyclonal antiserum to investigate a possible function to the isolated protein in binding of equine spermatozoa to homologous oviductal epithelial cells or zona pellucida. Incubation with antigen-binding fragments or IgG purified from the antiserum did not inhibit binding of equine spermatozoa either to oviductal epithelial cells or the zona pellucida. On ultrastructural examination, the antibody bound exclusively to the cytoplasmic side of the periacrosomal plasma membrane of equine and macaque spermatozoa. Microsequence analysis of 13 residues of sequence showed strong homology with a number of angiotensin converting enzymes: An 84% identity was identified with testis specific and somatic forms of human and mouse angiotensin-converting enzyme. Immunocytochemistry and immunoblot analysis established that the protein is specific for the periacrosomal membrane of ejaculated, epididymal, and testicular stallion spermatozoa.
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PMID:Isolation and characterization of a protein with homology to angiotensin converting enzyme from the periacrosomal plasma membrane of equine spermatozoa. 929 75

REP38 is a rabbit epididymal secretory protein of 38 kDa that has recently been shown to interact with spermatozoa. A rabbit epididymal cDNA expression library was screened with a polyclonal antibody raised against REP38. A single clone (REP38-c1) with an open reading frame encoding a polypeptide of 666 amino acids was obtained. Cleavage of a 22-amino acid N-terminal signal peptide revealed a mature protein with a theoretical molecular mass of 74.5 kDa. Northern blot analysis revealed the presence of two cross-hybridizing transcripts of approximately 1.3 and 2.5 kilobases that appear to result from alternative mRNA splicing. This finding may explain the discrepancies between the observed (38 kDa) and deduced molecular mass of REP38. Expression of both transcripts was epididymis specific and was detected only in regions 2-6. During development, the expression of REP38-c1 mRNA was initiated between 1 and 2 mo postnatum and therefore precedes the appearance of sperm within the lumen of the epididymis. These findings are in agreement with the immunohistochemical localization of the REP38 protein. Androgen deprivation induced by orchidectomy reduced REP38-c1 mRNA levels below the limit of detection, an effect that was reversed by administration of exogenous testosterone. Although REP38-c1 mRNA was detected only in the rabbit epididymis, database searches indicated homology with two rat testis specific cDNAs, KTT4 and odf2, which encode sperm outer dense fiber proteins.
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PMID:Rabbit epididymal secretory proteins. III. Molecular cloning and characterization of the complementary DNA for REP38. 1208 11

A decade ago a novel sperm protein associated with the fertility of sperm was discovered by quantifying individual proteins in the sperm membrane proteome of cauda epididymal sperm from rats exposed to epididymal toxicants that compromised the fertility of these sperm. Upon identification, this protein (SP22) was found to a ubiquitous, highly conserved protein never before observed in the male reproductive tract. The expression of SP22 in sperm appears driven by a testis specific mRNA transcript, and the molecule is translocated from the cytoplasmic droplet of rete testis sperm to the equatorial segment of epididymal and ejaculated sperm. The appearance of SP22 mRNA and protein coincide with the formation of pachytene spermatocytes and round spermatids, respectively, and given this testis ontogeny of SP22, we validated its use as a biomarker of fertility by extending our studies to toxicants that target spermiogenesis. Studies of both epididymal and testicular toxicants now have demonstrated that compromised SP22 gene expression is sensitive and correlated with fertility. Importantly, this applies to ejaculated sperm as well as epididymal sperm. With the goal of developing a user-friendly diagnostic assay for SP22 on epididymal and ejaculated sperm, we are attempting to identify exposed, functional domains of the protein. For this, we have generated antibodies to both full length and truncated SP22 recombinants, as well as antibodies to synthetic SP22 peptides. Each antibody has been characterized for its ability to inhibit fertilization both in utero and in vitro. Linear epitope mapping has been done for each antibody, and synthetic peptides corresponding to each epitope have been used in competition experiments designed to elucidate exposure on the sperm surface and function. Most of the linear epitopes identified appear to be exposed although there are relative differences in the degree of their exposure. Interestingly, one of the exposed epitopes does not appear to be functional, at least by itself. Many more domains of the molecule need to be studied, but based on our findings with the epitopes already identified, it seems a combinatorial targeting strategy may be beneficial. If one assumes that the protein's role in fertility resides in a single exposed epitope, or some combination of exposed epitopes, such targeting may also ultimately lead to successful modulation of the fertilizing potential of sperm.
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PMID:Saga of a sperm fertility biomarker. 1821 78