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)

Prostaglandin D2 synthase (PGDS) is a major epididymal secretory protein in several species. We quantified PGDS in ram and bull semen using a specific antiserum. Strong variations in PGDS concentration existed between animals. In the bull, the highest concentrations were found preferentially in animals with normal or high fertility, as was previously suggested. However, low concentrations were found in males with all ranges of fertility, suggesting that the function of PGDS either is not necessary for male fertility or can be assumed by other proteins when its concentration is low. In the ram and stallion, cDNA and deduced protein sequences of PGDS were obtained by reverse transcription-polymerase chain reaction and showed that PGDS possessed the sequences involved in the three-dimensional folding characteristic of the lipocalin family and a cysteine at position 65 that is involved in the enzymatic activity. The enzymatic activity of PGDS was estimated in the ram by in vitro incubation of epididymal-isolated tubules with radioactive arachidonic acid. Prostaglandin (PG) D2 represented approximately 10% of the PGs produced in the lumen, irrespective of the presence or absence of luminal PGDS, suggesting that this protein is not involved in PGD2 biosynthesis. These results were corroborated by the absence of conversion of PGH2 to PGD2 when epididymal fluids were incubated with PGH2. In the rat, inhibition of PG biosynthesis in vivo by nonsteroidal anti-inflammatory drugs for 60 days did not change spermatozoa mobility or male fertility. It is likely that PGDS, which has a structure similar to that of lipocalin, functions as a lipophilic carrier protein, because we have shown that epididymal PGDS binds retinoic acid and testosterone in vitro.
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PMID:Mammalian lipocalin-type prostaglandin D2 synthase in the fluids of the male genital tract: putative biochemical and physiological functions. 1180 63

Synthesis and secretion of certain epididymal proteins are regulated by lumicrine factors from the testis or from upstream regions of the excurrent ducts. Cysteine-rich secreted protein-1 (Crisp-1) is a major androgen regulated protein in the epididymal lumen fluid of the rat and other species. Previous research has demonstrated that disturbance of the luminal microenvironment through obstruction of the tract reduces Crisp-1 synthesis and secretion. The present study was undertaken to determine the influence of the luminal microenvironment on rat proximal caput epididymal Crisp-1 secretion into lumen fluid and on Crisp-1 gene expression in the same tubules. Western blot analysis demonstrated that Crisp-1 protein concentrations were reduced from control levels by perfusion with artificial caput fluid containing no testicular factors and were not increased by perfusion with fluids containing rete testis fluid proteins. Crisp-1gene expression was also reduced by perfusion with artificial caput fluid and not increased by perfusion with rete testis fluid proteins. Perfusion with artificial caput fluid containing 5alpha-dihydrotestosterone did increase one Crisp-1 transcript. This study demonstrates that intraluminal testicular proteins are not important co-regulators with androgens of Crisp-1gene expression or resulting Crisp-1 secretion into the rat proximal caput tubule lumen in vivo.
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PMID:On the regulation of Crisp-1 mRNA expression and protein secretion by luminal factors presented in vivo by microperfusion of the rat proximal caput epididymidis. 1189 14

The objectives of the present investigation were to study the interaction of protein D/E with the surface of rat epididymal spermatozoa and to assess its topology on the spermatozoa surface before and after deposition in the female reproductive tract. Protein D/E, a member of the cysteine-rich secretory protein (CRISP-1) family, has been proposed to be involved in sperm-egg membrane fusion. In vitro competitive photoactivated cross-linking experiments followed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and Western blot analysis revealed that protein D/E molecules specifically interact with two surface proteins exhibiting an M(r) approximately 120.0 kd and approximately 130.0 kd, respectively, on the sperm surface. In vitro treatment of epididymal spermatozoa with phosphatidylinositol specific-phospholipase C revealed the release of protein D/E molecules over the head region but not the tail region of spermatozoa. Indirect immunofluorescence experiments using polyclonal antibodies generated against a highly purified protein D/E preparation demonstrated that protein D/E molecules were bound to the surface of spermatozoa recovered from the epididymal and female reproductive tracts, even after 7 hours. These results indicate that protein D/E molecules interact with specific membrane proteins, and is subsequently covalently bound to the surface of spermatozoa via a glycosyl-phosphatidyl inositol linkage. In addition, protein D/E molecules remain covalently bound to spermatozoa after deposition in the female reproductive tract, an observation that is consistent with the proposed physiological function of the protein in the fertilization process.
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PMID:Binding of protein D/E to the surface of rat epididymal sperm before ejaculation and after deposition in the female reproductive tract. 1206 58

Acidic epididymal glycoprotein 1 (AEG1), also called cysteine-rich secretory protein 1 (CRISP1), is a member of the CRISP protein family which is characterized by 16 conserved cysteine residues at the C-terminus. The CRISP proteins are expressed in the male genital tract and are thought to be involved in sperm-egg fusion. Therefore, their genes are of interest as candidate genes for inherited male fertility dysfunctions and as putative quantitative trait loci for male fertility traits. In this report, the cloning and DNA sequence of 90 kb of horse genomic DNA from equine chromosome 20q22 containing the complete equine AEG1 gene are described. The equine AEG1 gene consists of eight exons spanning 31 kb. Analysis of equine AEG1 transcripts did not reveal any evidence for alternative splicing, however three different transcription start sites are used. The first transcription start site is located 20 nt downstream of a TATA box motif. Reverse transcription polymerase chain reaction analysis demonstrated that AEG1 is expressed in different parts of the epididymis, whereas it is hardly detectable in the testis. The naturally occurring diversity of the equine AEG1 gene in different horse breeds was investigated and several polymorphisms are reported, including one that affects the amino acid sequence. Finally, sequence comparisons revealed that the intronless equine PGK2 gene for the testis-specific phosphoglycerate kinase is located approximately 39 kb downstream of AEG1.
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PMID:Molecular characterization of the equine AEG1 locus. 1211

The mammalian epididymis secretes numerous proteins important for sperm maturation. Among these are proteins D and E, which belong to the CRISP family (cysteine-rich secretory proteins) and are the product of the Crisp-1 gene. These proteins have been the focus of a number of studies and have been implicated in sperm/egg fusion. Protein D and protein E have been purified to apparent homogeneity in several laboratories. Polyclonal antibodies raised against each protein typically cross-reacted with both proteins, suggesting that they were immunologically similar, if not identical. Our laboratory has previously reported the generation of a monoclonal antibody (mAb 4E9) that recognizes only protein E. Using mAb 4E9, the localization of protein E was shown to be domain specific on the sperm surface and there is processing of the protein in the fluid, with only the lowest molecular weight form associating with sperm. Subsequent purification and amino acid sequencing of protein D confirmed that proteins D and E are nearly identical and differ only by presence of the 4E9 epitope on protein E. Here we report the generation of antibodies to regions of amino acid sequence identity in proteins D and E. Using these antibodies, we demonstrate that protein D associates with the sperm head and that a portion of this protein may be proteolytically processed. In addition, we demonstrate that the proteolytic processing of protein E occurs in the carboxy terminal region of this protein. The data also suggest that a portion of protein D may also undergo processing, similar to that of protein E. Finally, we use these antibodies to demonstrate that proteins D and E are differentially expressed by the epididymal epithelium. Taken together, these data suggest that proteins D and E may have individual roles in sperm function.
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PMID:A comparative analysis of expression and processing of the rat epididymal fluid and sperm-bound forms of proteins D and E. 1213 91

Rat sperm epididymal glycoprotein DE belongs to the cysteine-rich secretory protein (CRISP) family and participates in sperm-egg fusion through its binding to complementary sites on the egg surface. To investigate the molecular mechanisms underlying the role of DE in gamete fusion, in the present work we expressed DE in a prokaryotic system, and examined the relevance of carbohydrates and disulfide bonds for the biological activity of the protein. Immunofluorescence and sperm-egg fusion assays carried out in the presence of recombinant DE (recDE) revealed that this protein exhibits the ability to bind to the DE-egg binding sites and to inhibit gamete fusion, as does native DE (nDE). Comparison of the proteins indicated, however, that the inhibitory ability of recDE was significantly lower than that of nDE. This difference would not be due to the lack of carbohydrates in the bacterially expressed protein because enzymatically deglycosylated nDE was as able as the untreated protein to inhibit gamete fusion. To examine whether disulfide bridges are involved in DE activity, the presence of sulfhydryls in nDE and recDE was evaluated by the biotin-maleimide technique. Results indicated that, unlike nDE, in which all cysteines are involved in disulfide bonds, recDE contains free thiol groups. Subsequent experiments showed that reduction of nDE with dithiothreitol significantly decreased the ability of the protein to inhibit gamete fusion. Together, these results indicate that whereas carbohydrates do not have a role in DE-mediated gamete fusion, disulfide bridges are required for full biological activity of the protein. To our knowledge, this is the first study reporting the relevance of structural components for the function of a CRISP member.
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PMID:Expression and structure-function analysis of de, a sperm cysteine-rich secretory protein that mediates gamete fusion. 1229 40

The cysteine-rich secretory protein (CRISP) family consists of three members called acidic epididymal glycoprotein 1 (AEG1), AEG2, and testis-specific protein 1 (TPX1), which share 16 conserved cysteine residues at their C-termini. The CRISP proteins are primarily expressed in different sections of the male genital tract and are thought to mediate cell-cell interactions of male germ cells with other cells during sperm maturation or during fertilization. Therefore, their genes are of interest as candidate genes for inherited male fertility dysfunctions and as putative quantitative trait loci for male fertility traits. In this report, the cloning and DNA sequence of 137 kb of horse genomic DNA from equine chromosome 20q22 containing the closely linked equine TPX1 and AEG2 genes are described. The equine TPX1 gene consists of ten exons spanning 18 kb while the AEG2 gene consists of eight exons that are spread over 24 kb. The expression of these two genes was investigated in several tissues by reverse transcription polymerase chain reaction analysis and Western blotting. Comparative genome analysis between horse, human, and mouse indicates that all three CRISP genes are clustered on one chromosomal location, which shows conserved synteny between these species.
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PMID:Molecular characterization of the equine testis-specific protein 1 (TPX1) and acidic epididymal glycoprotein 2 (AEG2) genes encoding members of the cysteine-rich secretory protein (CRISP) family. 1245 57

The CRES (cystatin-related epididymal spermatogenic) protein defines a new subgroup in the family 2 cystatins of the cystatin superfamily of cysteine protease inhibitors. However, unlike the ubiquitous expression of cystatin C, the Cres gene is preferentialy expressed in postmeiotic germ cells, the proximal caput epididymidis, and anterior pituitary gonadotrophs. Furthermore, CRES protein lacks two of the three consensus sites necessary for the cystatin inhibition of C1 cysteine proteases. Therefore, CRES may perform unique and tissue-specific functions in the reproductive and neuroendocrine systems. In the present review, we describe our studies on: 1. the Cres gene promoter and the transcriptional regulatory protein and their associated DNA binding sites that may be important for tissue-specific expression; and 2. the biochemical function of CRES protein. In brief, Northern blot, gel shift analyses, and transient transfection assays demonstrated that the C/EBP beta (CCAAT/enhancer binding protein) transcription factor is the predominant C/EBP family member expressed in the epididymis and gonadotroph cells and is necessary for high levels of Cres expression in these two tissues. In other studies, analyses of transgenic mice expressing a CAT reporter gene driven by 1.6 kb of Cres promoter revealed CAT mRNA and protein only in the germ cells. These studies suggest that the 1.6 kb of Cres 5' flanking sequence contains the required DNA elements for expression in the testis, but lacks the elements to correctly target expression of the reporter gene in the epididymis. Alternatively, repressor elements may be present. Finally, in vitro protease assays were performed to determine if CRES functions as a protease inhibitor. In contrast to cystain C, CRES did not inhibit the C1 cysteine protease papain but rather inhibited at nanomolar concentrations the serine protease PC2, a prohormone processing enzyme. Therefore, CRES is a new cross-class inhibitor that may regulate PC2 of PC2-like proteases and suggests a role for CRES in the regulation of prohormone and proprotein processing.
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PMID:[Cres (cystatin-related epididymal spermatogenic) gene regulation and function]. 1247 14

The cystatin-related epididymal spermatogenic (CRES) protein is related to the family 2 cystatins of the cystatin superfamily of cysteine protease inhibitors. However, CRES lacks sequences important for cysteine protease inhibitory activity and is specifically expressed in reproductive and neuroendocrine tissues. Thus, CRES is distinct from cystatins and may perform unique tissue-specific functions. The purpose of the present study was to determine whether CRES functions as a protease inhibitor in in vitro assays. In contrast to mouse recombinant cystatin C, recombinant CRES did not inhibit the cysteine proteases papain and cathepsin B, suggesting that it probably does not function as a typical cystatin. CRES, however, inhibited the serine protease prohormone convertase 2 (PC2), a protease involved in prohormone processing in the neuroendocrine system, whereas cystatin C showed no inhibition. CRES did not inhibit subtilisin, trypsin, or the convertase family members, PC1 and furin, indicating that it selectively inhibits PC2. Kinetic analysis showed that CRES is a competitive inhibitor of PC2 with a K(i) of 25 nM. The removal of N-terminal sequences from CRES decreased its affinity for PC2, suggesting that the N terminus may be important for CRES to function as an inhibitor. These studies suggest that CRES is a cross-class inhibitor that may regulate proprotein processing within the reproductive and neuroendocrine systems.
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PMID:The cystatin-related epididymal spermatogenic protein inhibits the serine protease prohormone convertase 2. 1258 66

The cystatin-related epididymal spermatogenic (CRES) and recently identified testatin and cystatin T proteins define a new subgroup within the family 2 cystatins of cysteine protease inhibitors. Members of the CRES subgroup are predominantly expressed in reproductive tissues and lack critical cystatin active-site sequences implying divergent functions. To determine whether there are additional members of the subgroup, we searched nucleotide databases and identified two novel genes that we designated Cres2 and Cres3. These genes, like other subgroup members, encode proteins with four conserved cysteine residues and predicted molecular weights characteristic of family 2 cystatins but have divergent cystatin inhibitory sequences. Furthermore, the genes exhibited reproductive-specific expression with Cres2 exclusively expressed in the epithelial cells of the proximal and midcaput epididymal regions and Cres3 expressed in the proximal caput epididymal epithelium, Sertoli cells of the testis, and early follicles and corpora lutea in the ovary. Additional studies showed that, like Cres, both Cres2 and Cres3 genes are dependent on testicular factors for epididymal expression. Taken together, CRES2 and CRES3 represent new members of a subgroup of cystatin family 2 proteins that likely carry out tissue-specific functions distinct from that of typical cystatins.
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PMID:Cres2 and Cres3: new members of the cystatin-related epididymal spermatogenic subgroup of family 2 cystatins. 1258 67


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