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:3.1.27.5 (RNase)
17,967 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

[1,2,6,7-3H]Testosterone (250 muCi) was administered to castrated male rats; after 30 min a labelled testosterone-receptor protein complex with a pI of 5.1 was recovered from the pancreatic cytosol. A labelled testosterone-receptor complex with an identical pI was also extracted from the nuclear fraction of rat pancreas after incubation of minced pancreatic tissue with 0.1 muM-]1,2,6,7-3H]testosterone for 30 min at 37 degrees C. Studies in vitro showed that [1,2,6,7-3H]testosterone was bound to a receptor protein focusing at a pI of 5.1 and with a Kd of 2 nM and a number of binding sites of 4.7 fmol/mg of protein in castrated male rats. The testosterone-receptor complex sedimented at 3.5 S in high-salt sucrose-density gradients, was excluded from Sephadex G-200 and Ultragel ACA-34, was stable towards treatment with dextran-coated charcoal, was relatively sensitive to heat, and was stable to treatment with deoxyribonuclease and ribonuclease, but was sensitive to treatment which proteinase. It is suggested that the pancreatic androgen receptor, which was also present in castrated female rats, may play a role in sex-steroid regulation of pancreatic function.
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PMID:Demonstration of an androgen receptor in rat pancreas. 18 42

We have investigated the ability of dehydroepiandrosterone (DHEA) to alter the production of interleukin-2 (IL-2) and to bind to a specific binding complex in antiCD3 epsilon activated T cells. Binding activity correlated with the presence of a specific DHEA binding complex in the cytosol and nuclei of DHEA-responsive T-cell hybridomas, as well as in CD4+ and CD8+ cells isolated from peripheral lymph nodes of normal mice. Scatchard analysis determined that intact lymphocytes and cytosolic fractions contained high affinity binding for [3H]DHEA (approx. 2.6 nM) with 1000-7000 binding sites existing per cell. Five of the T-cell hybridomas tested both responded to DHEA treatment with increased production of IL-2 and also contained specific high affinity [3H]DHEA binding. Four additional T-cell hybridomas were found to contain no specific [3H]DHEA binding and were also unresponsive to DHEA influences on IL-2 production. Sucrose density gradients demonstrated a 3-4s [3H]DHEA binding complex in high salt and a 7-8s binding complex in low salt. Specific binding was inhibited by preincubation of the cytosol fractions with either trypsin or chymotrypsin, or by heating to 60 degrees C for 1 h (less than 15% of control). [3H]DHEA binding was unaffected by preincubation of the cytosol fractions with ribonuclease, deoxyribonuclease, or phospholipase A. The DHEA-protein complexes bound to DNA-cellulose with the amount of binding being slightly increased by preincubation at 25 degrees C as compared to 4 degrees C. As expected, [3H]DHEA binding was inhibited by the addition of unlabeled DHEA, but was also modestly inhibited by dihydrotestosterone and cortisol. Binding of DHEA was unaffected by progesterone, dexamethasone, estradiol, androsterone, DHEAS, and beta-etiocholanolone at all concentrations tested. DHEA was incapable of inhibiting the binding of [3H]DHT to the androgen receptor or [3H]dexamethasone to the glucocorticoid receptor. Collectively, these findings suggest that murine T cells contain a specific DHEA receptor. We believe that DHEA is a steroid hormone that is directly involved in the regulation of IL-2 production by both normal and some T-cell hybridomas.
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PMID:The presence of a dehydroepiandrosterone-specific receptor binding complex in murine T cells. 135 1

Testosterone-resistant male mice hemizygous for the X-chromosome-linked mutant gene Tfm express detectable but severely reduced levels of androgen receptor mRNA, amounting to about 10% of the level found in normal male littermates. No structural abnormality could be identified in the coding region of the messenger by a series of RNase-protection assays. However, cell-free translation of RNAs transcribed in vitro from enzymatically amplified overlapping segments of exon 1 revealed a truncated receptor protein and helped to localize the site of premature termination. Sequence analysis of the relevant DNA segment disclosed that deletion of a single nucleotide in the hexacytidine stretch at position 1107-1112 alters the reading frame of the messenger and introduces 41 missense amino acids before a premature termination codon at position 1235-1237. Separately initiated carboxyl-terminal polypeptides are synthesized in vitro, starting probably at the in-frame AUG codon 1507-1509, which lies in a favorable context for translation initiation, and at the non-AUG codon 1144-1146. Transcriptional impairments of the Tfm gene were ruled out by a quantitative analysis of enzymatically amplified nuclear RNA precursors. No other change could be identified by sequencing the complete coding region of Tfm cDNA. The finding of the unsuspected termination codon and the evidence of internally initiated carboxyl-terminal polypeptides reconcile previous conclusions and account for all known phenotypic properties of the mutation.
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PMID:A single base deletion in the Tfm androgen receptor gene creates a short-lived messenger RNA that directs internal translation initiation. 192 21

Complementary DNA clones covering the coding region of the mouse androgen receptor (AR) were assembled by enzymatic amplification from testicular RNA and genomic DNA. The deduced amino acid sequence consists of 899 residues and departs from the rat sequence at 21 positions, 20 of which are in the amino-terminal trans-activation domain. A notable cluster of substitutions lies in the region of the long glutamine repeat at positions 174-195. The size heterogeneity of AR messengers suggested by previous blot hybridization experiments was examined by RNase protection analysis of sucrose gradient-fractionated poly(A) RNA from mouse liver. A predominant 10-kilobase long mRNA species was found to encode the AR, and a 3' noncoding portion longer than 5 kilobases was demonstrated by internal cleavage with RNase-H, followed by blot hybridization with a 3' probe. The sensitivity afforded by the use of homologous RNA probes in solution hybridizations allowed the demonstration in Tfm/Y mutant mice of an AR mRNA that covers the entire coding region, but is present at 10- to 20-fold lower levels than in normal animals. The detection of significant amounts of receptor messenger revives earlier suggestions of an AR protein in Tfm/Y mice and indicates, at variance with other conclusions, that the expression of this mutant AR is affected at a post-transcriptional level.
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PMID:Structure and size distribution of the androgen receptor mRNA in wild-type and Tfm/Y mutant mice. 217 22

This study identifies an intermediate-sized androgen receptor and characterizes its relationship with the 9.1S and 4.4S receptor forms. Under low ionic conditions, at 2-4 degrees C, there exists a 9.1S (+/- 0.17) (n = 30) oligomeric form which does not bind to DNA. Under high ionic conditions, this form dissociates to a 4.4S (+/- 0.08) (n = 18) monomeric form. When the salt concentration is lowered, the 4.4S monomer converts to a species with an intermediate sedimentation coefficient of 7.7S (+/- 0.15) (n = 17) which binds to DNA. Unlike the 9.1S oligomer the 7.7S form is not maintained by sodium molybdate under high ionic conditions but rather dissociates to the 4.4S monomer. To determine whether these forms were associated with RNA, the 7.7S form was incubated with RNase A and analyzed by density gradient centrifugation. The 7.7S form was digested fully by RNase to the 4.4S monomer. The 7.7S form demonstrated a buoyant density of 1.2459 +/- 0.014 g/cm3 (n = 6) in metrizamide gradients, suggesting a ribonucleoprotein component. The sedimentation coefficient of the 9.1S form was unaffected by RNase. These data suggest that the intermediate 7.7S receptor form is composed of 4.4S monomer associated with a ribonucleoprotein molecule(s).
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PMID:Properties of an intermediate-sized androgen receptor: association with RNA. 243 28

The transformed androgen receptor from rat submandibular gland converts to a faster sedimenting form (6-8S) on a glycerol gradient centrifugation after withdrawal of a transformation-inducing reagent (KCl or ATP). In this report, the association of cytosolic RNA with the transformed androgen receptor was investigated as a possible mechanism of molecular conversion of the androgen receptor. When the transformed and converted androgen receptors were treated with RNase A, these receptors sedimented at 4.5S in a low-salt glycerol gradient. Addition of RNA from rat submandibular gland to the RNase-Sepharose-treated transformed receptor caused a shift of receptor peak from 4.5S to 5.8S. RNA from rat submandibular gland, yeast RNA and E. coli rRNA inhibited DNA-cellulose binding of a RNase-treated transformed receptor in the absence of molybdate. These observations suggest that conversion from the transformed 4S androgen receptor to a 6-8S form resulted from the association of RNA(s) with the transformed receptor.
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PMID:Ribonucleic acid association with androgen receptor from rat submandibular gland. 245 Feb 27

Much clinical evidence indicates that androgens have beneficial effects in the treatment of breast cancer in women. Physiological concentrations of androgens strongly inhibit both basal and estrogen-induced cell proliferation in the human breast cancer cell line ZR-75-1 through their interaction with the androgen receptor. The present study shows that androgens strongly suppress estrogen receptor (ER) and progesterone receptor contents in this model, as measured by radioligand binding and anti-ER monoclonal antibodies. Similar inhibitory effects are observed on the levels of ER messenger RNA (mRNA) measured by ribonuclease protection assay. The androgenic effect is observed at subnanomolar concentrations of the nonaromatizable androgen 5 alpha-dihydrotestosterone, regardless of the presence of estrogens, and is competitively reversed by the antiandrogen hydroxyflutamide. Such data on ER expression provide an explanation for at least part of the antiestrogenic effects of androgens on breast cancer cell growth and moreover suggest that the specific inhibitory effects of androgen therapy could be additive to the standard treatment limited to blockade of estrogens by antiestrogens.
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PMID:Down-regulation of estrogen receptors by androgens in the ZR-75-1 human breast cancer cell line. 266 Dec 9

The addition of vanadyl ribonucleoside complex (VRC), a potent inhibitor of RNase, to the transformed 4.5S androgen receptor from rat submandibular gland caused an increase in the sedimentation coefficient to 7.0S. Moreover, VRC decreased the DNA-cellulose binding of the transformed receptor; 50% inhibition of the DNA-cellulose binding was achieved at 1.8 mM VRC. On the other hand, agents related to VRC and oxoanions of transient metals, such as ribonucleoside, vanadate, molybdate, tungstate and arsenate, exerted no effect on the DNA-cellulose binding ability of the receptor. These findings suggest that VRC binds to the transformed androgen receptor at the DNA-binding site and that both oxovanadium ion and ribonucleoside are indispensable for the binding of VRC to the transformed androgen receptor.
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PMID:Interaction of vanadyl ribonucleoside complex with the androgen receptor. 319 Jul 19

Binding experiments with the cytosolic androgen receptor from murine skeletal muscle yield with testosterone a biphasic saturation curve and a biphasic Scatchard plot. These binding characteristics result from the conversion of 8 S receptor (KD = 1,4 X 10(-10) M) into 4-5 S receptor (KD = 1,2 X 10(-9) M). This conversion is androgen dependent and is facilitated in vitro by either UV-irradiation or by methods known to activate steroid hormone receptor complexes to a nuclear binding form (e.g. high ionic strength or elevated temperature). The measured data show that both receptor forms are in a complex dissociation equilibrium. The reassociation of the 4-5 S receptor to form the 8 S complex is inhibited by RNase.
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PMID:Correlation of the 4-5 S form and the 8 S form of the cytosolic androgen receptor in murine skeletal muscle. 667 45

In studies with a synthetic androgen, R 1881, an androgen-binding component was found in the cytosol of human placental villi. Kinetic analysis indicated that the Kd value of this component was 1.4 nM at 0-4 degrees C and that binding of R 1881 amounted to 277 +/- 73 fmol/mg protein. glycerol density gradient ultracentrifugation showed a peak of binding activity in the 8S region in a medium of low ionic strength, but in the 4.5S region in a medium containing 9.5 M KCl. The R 1881-binding component was inactivated by mild heat- or trypsin-treatment, but not by treatment with DNase or RNase. Most of the R 1881-binding activity was sedimented at 20 to 40% saturation of ammonium sulfate. These findings indicate that the R 1881-binding component in human placental cytosol is quite similar in its characteristics to androgen receptors, which are present in various androgen-responsive organs. Testosterone was a more potent competitor of R 1881-binding than DHT or cyproterone acetate. Scatchard plots indicated that the binding site of testosterone was identical with that of R 1881. These findings suggest that the androgen receptor in placental cytosol is specific for testosterone. The Kd value for testosterone was calculated to be 3.2 nM.
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PMID:Androgen receptor in human placental villi. 697 Dec 89


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