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:3.1.27.1 (RNase)
16,360 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Under defined conditions, in the presence of 10 mg/ml of bovine serum albumin, cauda epididymal rat spermatozoa displayed vigorous motility, and a high proportion (81%) of eggs were fertilized. In contrast, no fertilization was observed after omission of albumin, or replacement of the protein by 10 mg/ml of cytochrome c, beta-globulin, gamma-globulin, hemoglobin, lysozyme, and polyvinylpyrrolidone, and 5 mg/ml of ribonuclease. However, high motility occurred in suspensions containing 3 x 10(6) spermatozoa/0.1 ml of medium with cytochrome c, beta-globulin, or gamma-globulin. In medium with 1 mg/ml of ovalbumin, 7% (2/29) eggs were fertilized. Use of defatted albumin resulted in a higher rate of fertilization than unmodified albumin (87 vs 70%), and this difference approached statistical significance. No fertilization was obtained in the presence of albumin presaturated with cholesterol. These results suggest that: (a) rat sperm cells failed to capacitate in the absence of albumin; (b) the protein exerted more than a nonspecific macromolecular effect; and (c) lipids associated with albumin may modify its ability to promote sperm capacitation.
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PMID:Influence of serum albumin on the fertilizing ability in vitro of rat spermatozoa. 125 Aug 65

The effects of hypophysectomy and hormonal replacement therapy on GH receptor (GH-R) gene expression was studied in rat adipose tissue with a cRNA probe corresponding to the amino-terminal of the hepatic GH-R. Male Sprague-Dawley rats, 50-65 days of age, were used. In all fat depots tested (epididymal, retroperitoneal, and sc), two transcripts with an estimated size of 4.0 and 1.2 kilobases (kb), respectively, were detected. An intermediate-size transcript (2.6 kb) was sometimes observed. Also, isolated adipocytes and adipocyte precursor cells from the epididymal fat pad expressed these GH-R transcripts. The pituitary dependance of GH-R gene expression was analyzed in epididymal fat. Hypophysectomies were performed at 50 days of age, and the rats were then given replacement therapy with L-T4 (10 micrograms/kg.day) and hydrocortisone (400 micrograms/kg.day). Hypophysectomy decreased the abundance of both the 4.0 and the 1.2-kb transcripts, an effect that in part was restored by GH treatment. A solution hybridization RNase protection assay was then used to further characterize the effect of GH treatment of hypophysectomized rats on GH-R gene expression. A single injection of human GH (100 micrograms/rat) increased GH-R mRNA levels within 1 h, and maximal levels were reached between 3-12 h after the injection. The increase in GH-R mRNA levels was dose dependent and was observed also after prolonged treatment (1 or 5 mg/kg.day for 6 days) with bovine GH. These results confirm that GH-R mRNAs are present in rat adipose tissue from different fat depots. GH-R transcripts of the same estimated size were detected in isolated adipocytes and adipocyte precursor cells. Furthermore, the results show that there is a rapid and GH-dependent regulation of GH-R mRNA levels in adipose tissue.
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PMID:Expression and regulation of growth hormone (GH) receptor messenger ribonucleic acid (mRNA) in rat adipose tissue, adipocytes, and adipocyte precursor cells: GH regulation of GH receptor mRNA. 171 28

The RNase-colloidal gold procedure for the ultrastructural localization of RNA was used for rat testis. Along with other structures, it was found that the testicular sperm nucleus was well stained. Similar labelling was observed in the nucleus of rat epididymal sperm and human sperm. The RNA was extracted from sperm and analyzed by electrophoresis on 10% polyacrylamide gel and 7 M urea. The electrophoretic profile revealed a complex set of bands ranging in size from tRNA to high molecular weight components. On the average, a content of about 0.1 pg of RNA per rat or human sperm was found.
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PMID:Presence of RNA in the sperm nucleus. 246 35

Epididymides from sexually mature rabbits contain a factor that induces a discrete reduction in the sedimentation coefficient of cytosolic estrogen receptors from various tissues (rabbit epididymis and accessory sex organs; rabbit, rat and mouse uterus) and of cytosolic progesterone receptors from the rabbit uterus. The factor is not species-specific since a similar activity was detected in extracts of mature rat epididymides. Although present in cytosol, the factor is obtained in much higher yield in hypertonic extracts of the nucleomyofibrillar fraction of mature rabbit epididymal tissue. Using rabbit uterine estrogen receptor as substrate, we have determined the following details about the rabbit epididymal factor: (1) it is tissue-specific (undetectable in extracts from rabbit accessory sex organs, testis, uterus, liver, lung, kidney and intestine); (2) it is age-dependent (undetectable in extracts from sexually immature rabbit epididymides); (3) its maintenance is testis-independent following its post-pubertal induction or activation; (4) it is primarily localized in the caput region of the epididymis; (5) it is inactivated by elevated temperature; (6) it is macromolecular in nature; (7) it is DNase- and RNase-resistant; (8) it is irreversibly inactivated by leupeptin, indicating that it is a protease; and (9) it is effective on unoccupied and occupied receptors.
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PMID:Structural conversion of cytosolic steroid receptors by an age-dependent epididymal protease. 391 13

Exogenous calf thymus whole histones showed a high degree of specificity to cause agglutination of rat epididymal spermatozoa. Histones had markedly greater (approximately 5-fold) agglutination activity than did salmon protamine whereas a variety of proteins, including strongly basic ones such as herring protamine sulphate, ribonuclease, cytochrome C and lysozyme, had no detectable agglutination activity. Histones F-3 and F-2a had the greatest activity for cell agglutination. Polyamines (5 mM), sialic acid (5 mM) and basic or acidic amino acids (10 mM) had no effect on histone (approximately 8 microM)-mediated sperm agglutination. 32P-Labelled histones showed a high specificity for binding to intact spermatozoa. The binding was saturable at a histone concentration of approximately 0.3 mg/ml and nearly completely displaced at saturating concentrations of native histones. Only unlabelled protamines competed to a small extent for binding of 32P-labelled histones to spermatozoa. The data are consistent with the view that histones bind specifically to sperm surface receptor sites before agglutination of cells.
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PMID:Histone-mediated agglutination of epididymal spermatozoa and the occurrence of histone receptors on the rat sperm surface. 725 26

Differential screening of a human epididymal cDNA library led to the isolation and characterization of a major epididymis-specific cDNA clone family, referred to as HE3. More detailed sequence and PCR analysis identified two different but homologous gene transcripts, HE3 alpha and HE3 beta. The former represents an mRNA of ca. 1 kb, encoding a putative small secretory polypeptide of 14903 MW. The HE3 beta transcript was only found as incomplete 3' fragments. Analysis of human genomic DNA by Southern blotting suggested the presence in the human genome of at least three independent HE3-related genes. Isolation of genomic clones for the HE3 alpha gene showed this to contain a single intron of 1.4 kb in the 5' noncoding region. Although genomic clones corresponding to HE3 beta could not be found, a third highly homologous gene, HE3 gamma, was identified as a potential pseudogene. Neither nucleotide nor encoded amino acid sequences of the HE3 gene family are related to any other known sequence in the central databases, and thus represents a novel human gene family, with at least three nonallelic members. Northern hybridization analysis showed that HE3 gene products are specifically expressed in the human epididymis, and not in any other tissue examined. Furthermore, except for the pig, no other nonprimate species has been identified to express homologous sequences in the epididymis. RNase protection assays showed that both the HE3 alpha and HE3 beta, but not the HE3 gamma genes, are expressed in the human epididymis.
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PMID:Major human epididymis-specific gene product, HE3, is the first representative of a novel gene family. 751 8

Three murine peroxisome-proliferator-activated-receptor (PPAR) genes were localised to chromosome 15 (PPAR alpha), chromosome 17 (PPAR beta) and chromosome 6 (PPAR gamma). The expression of the three PPAR RNAs was determined using a specific RNase protection assay. In liver RNA, PPAR alpha was expressed at the highest level, with 20-fold lower levels of PPAR beta, and very low levels of PPAR gamma. The three PPAR RNAs showed no sex-specific differences in expression, and the levels of these transcripts were unaffected by treatment of mice with testosterone or the potent peroxisome proliferator, methylclofenapate. In agreement with this data, the level of PPAR alpha protein in liver was unchanged after treatment of mice with methylclofenapate. Investigation of the tissue-specific distribution revealed that the PPAR alpha RNA was expressed at highest levels in liver, to moderate levels in kidney and brown adipose tissue, and at low levels elsewhere. PPAR beta was expressed at moderate levels in liver, and lower levels in other tissues, including brown adipose tissue. In contrast, PPAR gamma RNA was expressed at low levels in liver or epididymal white adipose tissue and at very low levels elsewhere, but was expressed at high levels in brown adipose tissue. The tissue distribution of these receptors suggests an important role in lipid metabolism and toxicity for individual members of the PPAR family. The expression of PPAR alpha and PPAR beta RNAs was examined in 13 strains of mice, and the levels of expression varied within a fourfold range. Polymorphism in the size of PPAR alpha RNA from Swiss-Webster mice was detected, and shown to be due to a 2-bp mutation in the 3' non-coding region of PPAR alpha in Swiss Webster mice.
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PMID:Chromosomal localisation, inducibility, tissue-specific expression and strain differences in three murine peroxisome-proliferator-activated-receptor genes. 758 49

Bovine seminal plasma (BSP) contains four similar acidic proteins, previously designated as BSP-A1, BSP-A2, BSP-A3, and BSP-30-kDa. These proteins are secreted by the seminal vesicles and coat the surface of the spermatozoa after ejaculation. The binding site of BSP proteins on the sperm surface has been identified as choline phospholipids on the plasma membrane. This study was undertaken to determine whether BSP proteins modulate capacitation of bovine spermatozoa induced by heparin. Bovine epididymal spermatozoa were washed and incubated in buffer containing BSP proteins and then washed and incubated with heparin. The percentage of capacitated spermatozoa was determined under the microscope after the acrosome reaction has been initiated with the addition of lysophosphatidylcholine. The results demonstrated that epididymal sperm undergo the acrosome reaction only in the presence of BSP proteins. This effect was concentration-dependent and reached a maximum level of a 3-5-fold increase at 20-40 micrograms/ml BSP protein concentrations. In contrast, ribonuclease (purified from bovine seminal fluid) or seminal fluid proteins depleted of BSP proteins (by sequential absorption of BSP proteins on gelatin-Agarose and DEAE-Sephadex columns) showed no significant potentiating activity. The purified BSP proteins were more active than crude alcohol precipitates of bovine seminal plasma. These results indicate that BSP proteins are regulatory factors of capacitation.
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PMID:Phosphatidylcholine-binding proteins of bovine seminal plasma modulate capacitation of spermatozoa by heparin. 763 45

Multiple gamma-glutamyl transpeptidase (GGT) messenger RNAs (mRNAsII-IV) are expressed in a region-specific manner in the rat epididymis. In the present study, we examined the role(s) of plasma testosterone (T) and testicular factors in regulating the region-specific pattern and quantity of GGT mRNAs expressed along the epididymal duct. Northern blot and ribonuclease protection analyses showed that bilateral orchiectomy for 1, 5, and 15 days dramatically reduced the expression of GGT mRNAsII-IV in the initial segment. Expression of GGT mRNAII and mRNAIII was maintained in the initial segment of orchiectomized animals receiving T implants that maintain normal serum T concentrations, but GGT mRNAIV expression remained low relative to sham-operated control values. Unilateral efferent duct ligation decreased GGT mRNAIV expression only in the initial segment. Hence, expression of GGT mRNAIV in the initial segment was not maintained by circulating T and required a factor(s) of testicular origin. In caput epididymidis, expression of GGT mRNAII and mRNAIII declined after orchiectomy and was not completely restored to control values in orchiectomized animals by plasma T alone, but also required a testicular factor(s). In contrast to the initial segment, expression of GGT mRNAIV in the corpus and cauda epididymidis did not require T and/or a testicular factor(s), as expression of this transcript remained unchanged in these regions after 1, 5, and 15 days of orchiectomy, orchiectomy and T replacement, and after unilateral efferent duct ligation. In the cauda epididymidis, expression of GGT mRNAII required circulating androgens and was unaffected by unilateral efferent duct ligation, whereas GGT mRNAIII expression was repressed by T. These data demonstrate that circulating T and a factor(s) of testicular origin differentially regulate the expression of each GGT mRNA in a region-specific manner.
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PMID:Expression of multiple gamma-glutamyl transpeptidase messenger ribonucleic acid transcripts in the adult rat epididymis is differentially regulated by androgens and testicular factors in a region-specific manner. 791 28

Few transcription factors in somatic cells of the testis and epididymis that could potentially regulate androgen-dependent developmental events during male gametogenesis have been identified. In this study we examined the regulation and expression of an orphan homeobox gene, Pem, which encodes a homeodomain related to those in the Prd/Pax gene family. RNase protection, in situ hybridization, and Northern blot analyses of wild-type and germ-cell-deficient mutant mice (W(V)/ W(V)) localized Pem transcripts to Sertoli cells of the testis. During prepubertal testicular development, Pem expression was dramatically induced on Day 9, approximately when germ cells are known to enter meiotic prophase. In adult mice, Pem transcripts were preferentially expressed in stages VII-VIII seminiferous epithelium, the androgen-dependent stages during which germ cells undergo the first step of meiosis. Pem gene expression depended on androgens and gonadotrophins, as demonstrated by a lack of expression in hypophysectomized mice, gonadotrophin-deficient hypogonadal (hpg) mutant mice, and androgen receptor-deficient (tfm) mutant mice. Injection of either testosterone or luteinizing hormone (LH) into hypophysectomized and hpg/hpg mice restored Pem expression in the testes to normal levels. The Pem gene was also shown to be specifically expressed in the proximal cauda and distal corpus regions of the epididymis, the regions where spermatozoa gain forward motility and fertilization competence. Pem expression in the epididymis did not depend on spermatozoa in the lumen of the testis, as shown in quaking (qk/qk) mutant mice, however, unlike in the testes, epididymal Pem expression required germ-cell-induced factors. Our results show that discrete cell types in male reproductive tissues transcribe and independently regulate the Pem homeobox gene. To our knowledge no transcription factors have previously been shown to depend on testosterone or LH for expression in Sertoli cells in vivo. Collectively, the data implicate Pem as a candidate to regulate a subset of androgen-dependent genes in the male reproductive system.
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PMID:Pem: a testosterone- and LH-regulated homeobox gene expressed in mouse Sertoli cells and epididymis. 890 61


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