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)

Sulfated glycoprotein-2 (SGP-2) is one of the major proteins secreted by rat Sertoli cells and epididymal cells in culture. The disulfide-linked dimeric protein secreted by Sertoli cells and found in seminiferous tubule fluid is composed of monomers of Mr 47 000 and 34 000 whereas the epididymal protein exhibits monomers of Mr 40 000 and 29 000. When both forms were chemically or enzymatically deglycosylated, they yielded proteins of similar molecular weight. No modification of the higher molecular weight testicular form by epididymal cells or fluids could be detected in incubation media. SGP-2 mRNA was localized in epididymal epithelium by in situ hybridization. Northern blot analysis indicated the testicular and epididymal mRNAs were of similar size. These findings suggest that the two forms of the protein occur because of tissue-specific post-translational modifications. The detergent-extracted protein from washed testicular spermatozoa is of the higher molecular weight form while epididymal sperm carry the lower molecular weight form. Immunohistochemical evidence suggests that the testicular form is removed prior to the initial segment of the epididymis and the epididymal form is applied in the proximal caput epididymidis. SGP-2 was immunolocalized to the sperm membrane at the ultrastructural level and was distinctly different from the immunolocalization of outer dense fiber proteins and fibrous sheath proteins.
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PMID:Localization of sulfated glycoprotein-2 (clusterin) on spermatozoa and in the reproductive tract of the male rat. 187 33

A previous study has characterized the major 47 kDa anti-sticking factor (ASF-I) from goat cauda-epididymal plasma (Roy, N., and Majumder, G.C., Biochim. Biophys. Acta, 991:114-122, 1989). This study reports the purification and characterization of ASF-II, another anti-sticking factor from the goat epididymal plasma. ASF-II was purified to apparent homogeneity by using concanavalin A-agarose affinity chromatography, DEAE-cellulose chromatography, alumina gel adsorption, and isoelectric focussing techniques. It showed a single protein band by both non-denaturing and SDS-polyacrylamide gel electrophoresis. ASF-II showed a molecular weight of 36,000 and a sedimentation constant of 2.4S. ASF-II is largely stable to heat treatment and it is a specific glycoprotein having high affinity and specificity for its anti-sticking action. At saturating concentration (1 nM) it inhibited adhesion of nearly 50% of spermatozoa to the glass surface of the haemocytometer counting chamber. Both the protein and sugar parts of the factor are essential for the anti-sticking activity since it lost its activity completely when treated with trypsin, L-fucosidase, or mannosidase. ASF-II does not coat the glass surface and it binds to spermatozoa. Data are consistent with the view that ASF-II has not been derived from the larger ASF-I molecule due to its enzymic modifications. Both ASF-I and -II had no effect on sperm forward motility as evidenced by spectrophotometric motility assays, indicating thereby the suitability of the factors to improve the existing sperm motility assays by eliminating the possibility of cell-sticking artifacts.
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PMID:Characterization of anti-sticking factor-II from goat epididymal plasma. 209 69

During dissolution of drops obtained by puncture of rat epididymis in distal caput, mid corpus, proximal and distal cauda we observed in the last two regions the appearance of a new sperm association which we call rosette and the formation in the same two regions of dense clusters of non-motile degenerating spermatozoa already described in the rat vas deferens. Rosettes become organized in the proximal cauda by head to head sperm contact through a filamentous PAS positive material. By video microscopy was observed the dilution of a dense drop of cauda epididymal content in a balanced salt solution at 36 degrees C. In less than 3 min, rosettes become dispersed into single sperm with a display of intense motility which starts immediately after dilution. A glycoprotein with cohesive properties secreted by the epididymal epithelium is postulated as the factor promoting rosette formation. We confirm that dense clusters correspond to degenerating spermatozoa and describe its first appearance in the epididymal proximal cauda with increase in number toward vas deferens.
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PMID:Sperm association in the rat epididymis. 213 4

Eight monoclonal antibodies (McAbs), directed against antigens on rat cauda epididymal spermatozoa, were tested for their capacity to interfere with fertilization in vitro as a means of identifying molecules with a potential role in sperm-egg recognition and fusion. Antigens recognized by the McAbs were visualized on live spermatozoa by indirect immunofluorescence (IIF) and characterized by immunoblotting. Five McAbs (designated 1B5, 2C4, 4B5, 5B1, and 8C4) recognized antigens specifically on the sperm acrosome and three (designated 2B1, 2D6, and 6B2) bound to the flagellum. Of the eight McAbs investigated, three (2B1, 2C4, and 6B2) were effective in blocking fertilization in vitro when added as culture supernatants to mixtures of sperm and eggs. McAb 6B2 was inhibitory due to its ability to agglutinate spermatozoa. McAbs 2B1 and 2C4 did not agglutinate capacitated spermatozoa, had no observable effect on motility, and yet blocked fertilization in a dose-dependent manner. McAb 2C4 did not give a reaction on immunoblots, but the 2B1 antigen was identified as an Mr 40 kD glycoprotein. McAb 2B1 appeared to block fertilization at the level of zona binding, whereas the effects of 2C4 were directed more against zona penetration and/or fusion with the vitellus. When sperm-egg complexes were stained with 2C4 or 2B1 McAbs and viewed by IIF, all spermatozoa that were attached to the zona showed fluorescence on the head. These results suggest that different antigens on the rat sperm head participate in different aspects of the fertilization process and that during capacitation there is either exposure of these antigens or else they migrate to their site of action from the flagellum.
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PMID:Antigens on rat spermatozoa with a potential role in fertilization. 218 54

Studies of in vitro models demonstrate that a forward motility protein (FMP) is required for the initiation of forward motility in the immature epididymal spermatozoa. FMP is a heat-stable glycoprotein derived from epididymal plasma. During the epididymal maturation of spermatozoa in vivo, there is a marked increase of intrasperm pH and level of cyclic adenosine monophosphate (cAMP). Several studies suggest that exogenous FMP in concert with elevated intrasperm pH and level of cAMP initiates flagellar motility during the epididymal transit of sperm. cAMP activates sperm cytosolic cAMP-dependent protein kinases, which in turn phosphorylate multiple intrasperm phosphoproteins that may regulate flagellar motility. Exogenous calcium ion activates intact sperm motility, although it inhibits motility of demembranated cells on reactivation. Occurrence of cAMP-dependent type I and II protein kinases, a novel cAMP-independent protein kinase, and a phosphoprotein phosphatase has been demonstrated on the external surface of spermatozoa. The sperm surface has a coupled-enzyme system: ecto-cAMP-independent protein kinase and phosphoprotein phosphatase that regulate the phosphorylation and dephosphorylation of endogenous sperm ectophosphoproteins. The specific activities of these ecto-enzymes increase markedly during forward progression, suggesting that they may have a role in regulating flagellar motility.
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PMID:Biochemical parameters of initiation and regulation of sperm motility. 219 32

Epididymal ligation in the mouse induced unusual cells, called peculiar pale epithelial cells (hereafter, pale cells), specifically in the epithelium of the corpus epididymidis (ABE et al., 1982a, b). These pale cells had vacuoles with long microvilli on their inner surface. In this study, we found that the vacuoles of the pale cells occurred in normal mice and contained epididymal specific glycoprotein, sialoglycoprotein of 54,000 dalton (SGP54). This was elucidated by indirect immunofluorescence and avidin biotin complex techniques using monoclonal antibody T21 which specifically recognizes SGP54. These immunoreactive pale cells occurred in the distal caput and proximal corpus of the epididymidis. The relationship between the pale cell and SGP54 is discussed.
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PMID:Epithelial cells with vacuoles containing 54,000 dalton sialoglycoprotein in the mouse epididymal duct. 220 51

Buffalo blood serum is a potent source of antisticking factor (ASF) that inhibits with high affinity adhesion of goat epididymal spermatozoa to the glass surface of hemocytometer counting chamber. The serum is also capable of inhibiting glass-sticking of spermatozoa of the buffalo, ram, and bull. The serum ASF activity is nondialyzable and stable to heat treatment at 100 degrees C for two minutes. The activity of the serum ASF was lost completely when treated with trypsin (50 micrograms/ml) at 37 degrees C for thirty minutes indicating the polypeptide nature of the ASF. Serum ASF activity consists of at least two factors (A and B) as shown by concanavalin A-agarose affinity chromatography. ASF-A and -B represent nearly 75% and 25% of the total serum ASF activity. ASF-B is a glycoprotein as it binds with high affinity to concanavalin A. The sera of species such as man, goat, and rat possess ASF activity.
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PMID:Antisticking protein factors in buffalo blood serum. 222 76

Mannostatin A is a metabolite produced by the microorganism Streptoverticillium verticillus and reported to be a potent competitive inhibitor of rat epididymal alpha-mannosidase. When tested against a number of other arylglycosidases, mannostatin A was inactive toward alpha- and beta-glucosidase and galactosidase as well as beta-mannosidase, but it was a potent inhibitor of jack bean, mung bean, and rat liver lysosomal alpha-mannosidases, with estimated IC50's of 70 nM, 450 nM, and 160 nM, respectively. The type of inhibition was competitive in nature. This compound also proved to be an effective competitive inhibitor of the glycoprotein-processing enzyme mannosidase II (IC50 of about 10-15 nM with p-nitrophenyl alpha-D-mannopyranoside as substrate, and about 90 nM with [3H]mannose-labeled GlcNAc-Man5GlcNAc as substrate). However, it was virtually inactive toward mannosidase I. The N-acetylated derivative of mannostatin A had no inhibitory activity. In cell culture studies, mannostatin A also proved to be a potent inhibitor of glycoprotein processing. Thus, in influenza virus infected Madin Darby canine kidney (MDCK) cells, mannostatin A blocked the normal formation of complex types of oligosaccharides on the viral glycoproteins and caused the accumulation of hybrid types of oligosaccharides. This observation is in keeping with other data which indicate that the site of action of mannostatin A is mannosidase II. Thus, mannostatin A represents the first nonalkaloidal processing inhibitor and adds to the growing list of chemical structures that can have important biological activity.
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PMID:Mannostatin A, a new glycoprotein-processing inhibitor. 227 38

A monoclonal antibody designated 'EC-1' was derived from a fusion of myeloma cells with lymphoid tissue from a syngeneically multiparous, but otherwise unimmunized, mouse and was selected by screening for reactivity with teratocarcinoma cells. The IgM antibody binds to the cell surface of ova, zygotes, and 2-cell embryos. Binding is not detected on the 4- or 8-cell embryo but reappears on the morula and blastocyst. EC-1 binds to the trophoblast but not to the inner cell mass of in vitro attached blastocysts and the ectoplacental cone of the peri-implantation embryo. In adult tissues, EC-1 binds to the follicular cells of the ovary, the lining epithelium of the pregnant uterus, the interstitial region of the testes and to epididymal but not testicular sperm. In nongonadal tissues EC-1 binds to an epitope located in some, but not all, regions of connective tissues associated with basement membrane. The antigen detected by EC-1, as expressed on teratocarcinoma-derived cell line PYS-2, is a large glycoprotein which is sensitive to reduction. EC-1 inhibits in vitro fertilization and partially inhibits in vitro development of in vitro fertilized ova. The possible implications of EC-1 binding and activity are discussed.
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PMID:A monoclonal antibody, EC-1, derived from a syngeneically multiparous mouse alters in vitro fertilization and development. 241 3

A glycoprotein, designated CMB-1, has been identified in media from Sertoli cell-enriched cultures that increases in concentration in response to follicle-stimulating hormone (FSH) and testosterone. Subsequent studies indicated that CMB-1 is immunologically related to albumin and alpha-fetoprotein and is concentrated in the luminal compartment of the testis in adult rats. Thus, CMB-1 was termed testibumin. The goal of the present study was to determine the concentrations of this protein in testes, epididymides, and serum of normal rats between 10 and 180 days of age and to compare them to rat androgen-binding protein (rABP). Testibumin concentration in rat testes increased with age and peaked at Day 60; thereafter, unlike rABP, its concentration declined, reaching a plateau by 150 days of age. Testibumin concentration in the epididymal compartment also increased with age and peaked at Day 90; thereafter, its concentration remained relatively unchanged. Unlike rABP, which accumulates in the caput epididymis, testibumin did not accumulate preferentially in any particular region of the epididymis. In spite of the marked changes of testibumin concentration in the male reproductive tract, the levels in blood remained relatively constant between 10 and 180 days of age. In adult male and female rats, the serum concentrations of testibumin were similar. Following orchiectomy, serum testibumin concentration decreased by 50% with an apparent t1/2 of approximately 8 h. The presence of immunoreactive macromolecules in other species that share epitopes with rat testibumin was also investigated. Material in human sera and extracts of human and monkey testes cross-reacts with rat testibumin. After [35S]methionine was added to the primary Sertoli cell-enriched cultures, anti-testibumin antiserum selectively immunoprecipitated a radiolabeled protein with the same electrophoretic mobility as purified testibumin on sodium dodecyl sulfate (SDS)-polyacrylamide gels. We conclude that 1) rat testibumin is synthesized and secreted by Sertoli cell-enriched cultures; 2) the relative concentrations and distribution of testibumin in testis, epididymis, and serum of the rat as a function of age are strikingly different from those of rABP; 3) rat testibumin shares epitopes with proteins in human serum and testicular extracts of monkey and man.
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PMID:The distribution of rat testibumin in the male reproductive tract. 244 71


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