Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:2.7.7.49 (reverse transcriptase)
31,746 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Although enzymatic processes involved in the formation of active steroids are well known, less information is available about the enzymes responsible for the metabolism of these hormones. Moreover, the expression of these catabolic enzymes, which include UDP-glucuronosyltransferases, may play a role in the regulation of the level and action of steroid hormones in steroid target tissues. Previous studies have shown that the cynomolgus monkey contains high levels of circulating androgen glucuronides, indicating that it represents the best animal model to study the glucuronidation of steroids in extrahepatic tissues. Two cDNA libraries were constructed from monkey liver and prostate mRNA, and a novel UDP-glucuronosyltransferase UGT2B cDNA, UGT2B19, was isolated from both libraries. The UGT2B19 cDNA is 2108 bp in length and contains an open reading frame of 1584 bp encoding a protein of 528 residues. The UGT2B19 cDNA clone was transfected into HK293 cells and a stable cell line expressing UGT2B19 protein was established. The activity of UGT2B19 on 3alpha-hydroxy and 17beta-hydroxy positions of steroids was demonstrated. The enzyme also conjugates xenobiotics including eugenol, 1-naphthol and p-nitrophenol. Kinetic analysis revealed that UGT2B19 glucuronidates steroids with Km values of 1.6, 2.6 and 4.3 microm for testosterone, etiocholanolone and 5beta-androstane-3alpha,17beta-diol, respectively. UGT2B19 transcript was detected, by specific reverse transcriptase-PCR analysis in the liver, ovary, prostate, colon, spleen, kidney, pancreas, brain, cerebellum, mammary gland and epididymis. The molecular characterization of simian UGT2B19 demonstrates relevance of using monkey as an animal model to study and understand steroid glucuronidation in extrahepatic target tissue.
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PMID:Molecular cloning, expression and characterization of a monkey steroid UDP-glucuronosyltransferase, UGT2B19, that conjugates testosterone. 1010 98

The EP2 gene codes for a family of androgen-dependent, epididymis-specific secretory proteins. Using probes derived from human HE2 cDNA, a chimpanzee epididymal cDNA library was screened. Five variants of chimpanzee EP2 cDNA were identified. Variant 1 (EP2A) is the chimpanzee ortholog of HE2. Variant 2 (EP2B) has an alternative 5' end. Variant 3 (EP2C) has an alternative 3' end. Two additional variants were identified by reverse transcriptase-polymerase chain reaction analysis. Variant 4 (EP2D) and variant 5 (EP2E) appear to lack an exon, resulting in a shift in the open reading frame. Presumably, the 5 variants originate from the same gene and result from alternative promoters and alternative splicing. Each of the putative proteins encoded by these variant messages has a leader sequence characteristic for a secretory protein. After removal of the leader sequence, each of these proteins is predicted to consist of 1 or 2 out of 4 possible peptide modules. Two of these modules have no recognizable homology to known proteins. The other 2 modules have a distribution of cysteine residues characteristic for beta-defensins, a family of proteins with antimicrobial activity.
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PMID:Multiple promoter and splicing mRNA variants of the epididymis-specific gene EP2. 1081 50

Differential display reverse transcriptase-polymerase chain reaction (DDRT-PCR) was used to identify a novel retrovirus, designated SC1, that is expressed at high levels in rat granulosa cells and prepubertal Sertoli cells. The initial DDRT-PCR screen was performed using RNA from cultured prepubertal rat Sertoli cell, liver, and brain samples. SC1 was detected in the prepubertal rat Sertoli cell samples but not in those from liver and brain. SC1 cDNA was 6 kilobases in length and contained regions encoding for the gag, pol, and env retroviral proteins. Northern blot analysis failed to detect expression of the SC1 gene in total RNA isolated from adult brain, heart, spleen, lung, liver, skeletal muscle, kidney, prostate, and epididymis. Similarly, Northern blot analysis of testes from rats at various ages of development showed that high-level expression of the SC1 gene was limited to prepubertal testis samples. In situ hybridization analysis localized the SC1 mRNA to the seminiferous tubules of prepubertal testes and at a much lower level in Sertoli cells of adult testes. Northern blot analysis of total RNA isolated from Sertoli cells from 20-, 27-, and 35-day-old rat Sertoli cells and type A spermatogonia, pachytene spermatocytes, and round spermatids showed expression of the SC1 gene to be restricted to 20- and 27-day-old Sertoli cells, with no expression detected in germ cells. Furthermore, Northern blot analysis also showed expression of the SC1 gene in rat ovaries, and the level of expression was affected during eCG/hCG-induced ovulation. Expression of SC1 mRNA was localized by in situ hybridization of eCG-treated ovaries to the granulosa cell layer in developing follicles. Southern blot analysis showed SC1 to be endogenous in the rat and absent in mouse and human cell genomes. Transient transfection assays using the SC1 promoter region showed high promoter activity in MSC-1 and cultured prepubertal rat Sertoli cells, and no activity in 3T3 or MCF-7 cell lines.
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PMID:Identification of a novel retrovirus expressed in rat Sertoli cells and granulosa cells. 1156 55

Differential display-reverse transcriptase-polymerase chain reaction was used to examine Sertoli cell gene expression. As a result, two new members of the mouse cystatin multigene family were isolated and named cystatin SC (cystatin-related gene expressed in Sertoli cells) and cystatin TE-1 (cystatin-related gene highly expressed in testis and epididymis). The full-length cDNA sequence of cystatin SC contains an open reading frame that encodes a putative signal peptide of 20 amino acids and a mature protein of 110 amino acids, whereas that of cystatin TE-1 encodes a 128 amino acid protein with a predicted signal peptide of 21 amino acids. Both of the deduced amino acid sequences contain four highly conserved cysteine residues in precise alignment with other cystatin family members. The derived cystatin SC and TE-1 amino acid sequences lack some of the specific, highly conserved motifs believed to be necessary for cysteine proteinase inhibition activity. Northern blot analysis revealed that cystatin SC mRNA was detected only in the testis, whereas the cystatin TE-1 gene was highly expressed in testis and epididymis with very low expression in ovary and prostate. In situ hybridization showed that cystatin SC mRNA was localized mainly to Sertoli cells with an obvious stage-dependent expression, and that cystatin TE-1 mRNA was predominantly expressed in Sertoli cells without apparent stage-dependent expression. Cystatin TE-1 mRNA, as displayed by in situ hybridization, was expressed only in the epithelial cells of the proximal caput region of the epididymis. The unusual amino acid sequence and highly restricted expression suggests that cystatins SC and TE-1 play a very specialized role in the testis and epididymis.
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PMID:Identification and characterization of testis- and epididymis-specific genes: cystatin SC and cystatin TE-1. 1244 65

Guanylyl cyclase C (GC-C) is a membrane-associated form of guanylyl cyclase and serves as the receptor for the heat-stable enterotoxin (ST) peptide and endogenous ligands guanylin, uroguanylin, and lymphoguanylin. The major site of expression of GC-C is the intestinal epithelial cell, although GC-C is also expressed in extraintestinal tissue such as the kidney, airway epithelium, perinatal liver, stomach, brain, and adrenal glands. Binding of ligands to GC-C leads to accumulation of intracellular cGMP, the activation of protein kinases G and A, and phosphorylation of the cystic fibrosis transmembrane conductance regulator (CFTR), a chloride channel that regulates salt and water secretion. We examined the expression of GC-C and its ligands in various tissues of the reproductive tract of the rat. Using reverse transcriptase and the polymerase chain reaction, we demonstrated the presence of GC-C, uroguanylin, and guanylin mRNA in both male and female reproductive organs. Western blot analysis using a monoclonal antibody to GC-C revealed the presence of differentially glycosylated forms of GC-C in the caput and cauda epididymis. Exogenous addition of uroguanylin to minced epididymal tissue resulted in cGMP accumulation, suggesting an autocrine or endocrine activation of GC-C in this tissue. Immunohistochemical analyses demonstrated expression of GC-C in the tubular epithelial cells of both the caput epididymis and cauda epididymis. Our results suggest that the GC-C signaling pathway could converge on CFTR in the epididymis and perhaps control fluid and ion balance for optimal sperm maturation and storage in this tissue.
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PMID:Expression of the receptor guanylyl cyclase C and its ligands in reproductive tissues of the rat: a potential role for a novel signaling pathway in the epididymis. 1244 76

Defensins are antimicrobial peptides that play a major role in innate immunity. Using reverse transcriptase-polymerase chain reaction, immunochemistry, or both, we performed a search of all presently known defensins in rat testis, epididymis, and isolated testicular cells; in mouse testis and epididymis; and in human testis and ejaculates. In the rat, all alpha- and beta-defensins except RNP-4 were expressed within the testis, whereas alpha-defensins RNP1-2, RNP-4, and beta-defensins RBD-1 and RBD-2 were present within the epididymis. In the mouse, the cryptdin transcripts CRS1C, mBD-1, and mBD-2 were detected in the testis and epididymis, whereas mBD-3 and mBD-4 were expressed only in the epididymis, and CRS4C was absent in both organs. In the human testis, transcripts for four known defensins were expressed with the consistent exception of HBD-2 and HBD-3. In rat interstitial tissue, resident macrophages expressed most of the defensins studied, whereas Leydig cells produced only RBD-2. In contrast, all studied defensins except RNP-4 were present in the seminiferous tubules. Within these tubules, peritubular and Sertoli cells expressed most of the studied alpha- and beta-defensins, whereas spermatogonia displayed only alpha-defensins, but at relatively high levels. Meiotic pachytene spermatocytes expressed only beta-defensins, whereas postmeiotic spermatids and their cytoplasmic lobes displayed both types. In humans, the HBD-1 peptide was expressed mainly in the germ line from pachytene spermatocytes to late spermatids. The peptide was also present in ejaculated spermatozoa and seminal plasma, where multiple soluble forms were present. Finally, high salt concentration or dithiothreitol-sensitive cationic extracts from human seminal plasma were indeed found to display antimicrobial activity. We conclude that the male reproductive tract produces defensins that most probably assume an important, innate organ defense system against pathogens.
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PMID:Expression of antimicrobial defensins in the male reproductive tract of rats, mice, and humans. 1249

The expression pattern of EP2 variants was examined in the rhesus monkey (Macaca mulatta). Using reverse transcriptase-polymerase chain reaction and rapid amplification of complementary cDNA protocols, 11 message variants were identified in rhesus epididymis, only three of which (EP2B, EP2C, and EP2E) have previously been reported. The most abundant variant found in human, EP2A, was not found in rhesus. Seven of the eight new rhesus EP2 variants (EP2J-EP2Q) use previously unidentified 5'-splicing sites in exon 3, and four variants use three previously unidentified exons whose counterparts are present in the human EP2 gene. Overall, 3 of the 11 variants, EP2C, EP2E, and EP2Q, code for beta-defensin-like peptides whose probable physiological role is to protect the male reproductive tract against microbial invasions. Because of the complex splicing pattern that causes some downstream exons to be read in any of the three reading frames, the N-termini of the other eight EP2 peptide variants consist of a partial beta-defensin motif with three cysteines, followed by amino acid sequences that have no recognizable homology to known proteins.
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PMID:EP2 splicing variants in rhesus monkey (Macaca mulatta) epididymis. 1260 16

In the present study, we developed a novel method to analyze the calcium (Ca2+) signal in living slices of mouse caput epididymides by applying calcium imaging on Fura-2-loaded vibratome slices. The data revealed that in epithelial cells of mouse caput epididymides, ATP induces a rapid Ca2+ signal that is sustained after 60 sec. Preincubating the sections in Ca2+-free medium in the presence of EGTA did not affect the amplitude of the ATP-induced Ca2+ signal, indicating the presence of P2Y type purinergic receptors and phospholipase C activity. Furthermore, ATP induced a similar Ca2+ signal in the different subregions of caput epididymides. The P2X type ion-gated purinergic receptors could also be responsible for the ATP-induced Ca2+ signal because immunohistochemical and reverse transcriptase-polymerase chain reaction analyses showed that P2X1, P2X2, P2X4, P2X7, P2Y1, and P2Y2 receptors were expressed in the epididymis. We propose that P2X and P2Y receptor expression is vital for the normal function of epididymal epithelium and sperm maturation. Furthermore, the method we developed allows us to analyze the activity of various G protein-coupled receptors in intact epithelial cells of mouse epididymides, and other reproductive tissues as well.
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PMID:Adenosine triphosphate induces Ca2+ signal in epithelial cells of the mouse caput epididymis through activation of P2X and P2Y purinergic receptors. 1260 41

Linuron is an herbicide with weak androgen receptor (AR) antagonist activity. Exposure to linuron from gestation days (GD) 12 to 21 perturbs androgen-dependent male reproductive development. In utero exposure to 50-mg/kg/day linuron induces malformations of the epididymis and the vas deferens. The objective of this study was to identify alterations in gene expression within the testis and epididymis associated with abnormal Wolffian duct development and to correlate changes in gene expression with the gross morphology of the affected epididymides. Pregnant Sprague-Dawley rats were administered either corn oil vehicle or linuron (50 mg/kg/day) by gavage from GD 12 to 21 (n = 3-6 controls, n = 5-10 linuron-treated dams per time point). Changes in gene expression were evaluated in testes on GD 21 and in epididymides on GD 21 and postnatal day (PND) 7, using cDNA microarrays and confirmed by real-time reverse transcriptase polymerase chain reaction (RT-PCR) analyses. RNA was isolated from intact epididymides with reduced or no ductal coiling from the linuron groups, and epididymides with noncontiguous ducts were excluded. In the fetal testis, exposure to linuron did not result in reduced mRNA expression of the AR or that of several steroidogenic enzymes, supporting the hypothesis that linuron does not reduce fetal testosterone production. Linuron induced a significant decrease in AR mRNA expression in GD 21 epididymides. Significant changes in mRNA expression in GD 21 and PND 7 epididymides were also identified in the epidermal growth factor (EGF), insulin-like growth factor 1 (IGF-1), bone morphogenetic protein (BMP), fibroblast growth factor (FGF), and Notch signaling pathways. These pathways are involved in tissue morphogenesis. Changes in the expression of AR and IGF-1 receptors were detected by immunostaining in malformed epididymides from linuron-exposed rats. Linuron induced changes in epididymal gene expression suggestive of altered paracrine interactions between the mesenchyme and epithelial cells during development. The EGF, Notch, IGF-1, BMP4, and FGF signaling pathways may be involved in normal testosterone-mediated development of the Wolffian duct.
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PMID:Altered gene expression during rat Wolffian duct development in response to in utero exposure to the antiandrogen linuron. 1273 Jun 24

One role of the hedgehog (hh) signaling pathway during development is to assist in establishing pattern orientation in the embryo. The structure and function in the adult epididymis is highly patterned, and since the sonic hedgehog (Shh) pathway is known to be functional in the developing male tract and the expression of other pattern-influencing genes has recently been found in the adult epididymis, we have examined the adult mouse epididymis for Shh pathway molecules. Examination was at both the gene and protein level. Shh, the secreted signal molecule, patched (Ptc), its membrane receptor, and Gli-1, a downstream transcription factor, were detected at the gene level with semiquantitative reverse transcriptase-polymerase chain reaction (RT-PCR) and at the protein level with Western blot analysis. Immunohistochemical localization further detected Shh specifically in the epididymal epithelium. It was hypothesized that efferent duct ligation (EDL) would alter epididymal segmentation within 30 days of the ligation, especially in the proximal segments of the caput epididymis. It was further hypothesized that these alterations would be correlated with changes in the expression of genes in the Shh pathway. EDL did not alter epididymal segmentation, but Shh, Ptc, and Gli1 expression was significantly altered at specific times after the ligation. The presence of the signaling pathway in the adult epididymis is a novel finding, as is the fact that in the distal epididymis, the specific gene expressions are altered by EDL. This suggests that the genes are capable of being regulated in a manner that is influenced by testicular contribution, and it implies that those genes have a function in the epididymis subject to that regulation.
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PMID:Sonic hedgehog pathway genes are expressed and transcribed in the adult mouse epididymis. 1522 40


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