Localization of the interferon-induced, 2-5A-dependent RNase gene (RNS4) to human chromosome 1q25.
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Chromosome Mapping↗
Biomedical subjects
A Zhou
Publications and source records attributed to A Zhou.
Regulation of interferon-alpha-inducible cellular genes in human immunodeficiency virus-infected monocytes.
Cellular mechanisms that control susceptibility to opportunistic infection in human immunodeficiency virus (HIV)-infected individuals remain poorly understood. HIV may induce certain cellular genes that restrict HIV replication and protect cells against other superinfecting viral pathogens. Indeed, HIV-infected monocytes resist infection by vesicular stomatitis virus (VSV). HIV-induced VSV interference in monocytes increases with time after HIV infection. Such interference was evident 6 h after HIV infection and reached maximal levels at 14 days. Monocytotropic but not T cell-tropic HIV strains elicited these effects, signaling a requirement for viral entry and/or replication. Viral interference was independent of interferon (IFN) and was unaffected by addition of neutralizing IFN-alpha and -beta antibodies. The well-described IFN-alpha-inducible antiviral pathways were examined to determine their relationship to the cellular mechanism(s) underlying VSV interference. HIV and IFN-alpha both induced the expression of 2-5A synthetase and Mx gene. In contrast, the guanylate-binding protein (GBP), 6-16, and 9-27 cellular genes were up-regulated by IFN-alpha but not HIV. MxA was detected in HIV-infected monocytes but not in uninfected monocytes. The association between Mx expression and resistance to VSV, coupled with previously described anti-VSV activities by human MxA, suggested that Mx may be an effector molecule for the HIV-induced anti-VSV activities. These results, taken together, suggest that HIV can induce antiviral cellular gene expression, independent of IFN.
2',5'-Oligoadenylate Synthetase↗
[Further study on the essence of acupoint specialty in mice].
Trace element, Cr+3 or V+5 are injected into acupoint of mice for pretreatment and then pentobarbital sodium injected into the same points, it is found that the element Cr+3 may shorten time of onset sleeping and prolong time of maintenance sleeping of injecting pentobarbital sodium at "Zusanli" point, while the element V+5 may shorten time of onset sleeping and prolong time of maintenance sleeping of injecting pentobarbital sodium at "Neigran" point. It indicates different trace elements can produce different influence on acupoint drug effect entering "Zusanli" or "Neiguan" point. The results mentioned above suggest that the different responses of different acupoints to same drug may be related to the different ion structures or different semi-conductive properties of the different acupoints.
Acupuncture Points↗
Expression cloning of 2-5A-dependent RNAase: a uniquely regulated mediator of interferon action.
2-5A-dependent RNAase, an interferon-induced enzyme that is activated by 5'-phosphorylated, 2',5'-linked oligoadenylates (2-5A), is implicated in both the molecular mechanisms of interferon action and the fundamental control of RNA stability in mammalian cells. Here we report the expression cloning and analysis of murine and human 2-5A-dependent RNAases. The 2-5A binding properties and RNAse activities of recombinant and naturally occurring forms of 2-5A-dependent RNAase were identical. Interferon induction of 2-5A-dependent RNAse expression was demonstrated by measuring the mRNA levels in cells treated with interferon and cycloheximide. Analysis of aligned murine and human 2-5A-dependent RNAse sequences revealed several intriguing features, including similarity to RNAase E, which is implicated in the control of mRNA stability in E. coli. Interestingly, a duplicated phosphate-binding loop motif was determined by deletion analysis and site-directed mutagenesis to function in the binding of 2-5A.
Amino Acid Sequence↗
Targeting RNA for degradation with a (2'-5')oligoadenylate-antisense chimera.
Antisense oligonucleotides hold considerable promise both as research tools for inhibiting gene expression and as agents for the treatment of a myriad of human diseases. However, targeted destruction of RNA has been difficult to achieve in a versatile, efficient, and reliable manner. We have developed an effective strategy for cleaving unique RNA sequences with 2-5A-dependent RNase, an endoribonuclease that mediates inhibitory effects of interferon on virus infection and is activated by 5'-phosphorylated 2'-5'-linked oligoadenylates known as 2-5A [pn5' A2'(p5' A2')mp5'A], resulting in the cleavage of single-stranded RNA predominantly after UpUp and UpAp sequences. To direct 2-5A-dependent RNase to cleave unique RNA sequences, p5' A2' p5' A2'p5'A was covalently linked to an antisense oligonucleotide to yield a chimeric molecule (2-5A:AS). The antisense oligonucleotide component of 2-5A:AS bound a specific RNA sequence while the accompanying 2-5A component activated 2-5A-dependent RNase, thereby causing the cleavage of the RNA in the targeted sequence. This strategy was demonstrated by inducing specific cleavage within a modified human immunodeficiency virus type 1 vif mRNA in a cell-free system from human lymphoblastoid cells. Because 2-5A-dependent RNase is present in most mammalian cells, the control of gene expression based on this technology--including therapies for cancer, viral infections, and certain genetic diseases--can be envisioned.
Adenine Nucleotides↗
The prohormone convertases PC1 and PC2 mediate distinct endoproteolytic cleavages in a strict temporal order during proopiomelanocortin biosynthetic processing.
Two subtilisin-like endoproteases called PC1 and PC2 are distributed in a tissue-specific manner in the pituitary and in the brain. AtT-20 cells and corticotropes of the anterior pituitary express primarily PC1 and perform a limited number of cleavages of the proopiomelanocortin (POMC) precursor during biosynthesis. Melanotropes of the intermediate pituitary express both PC1 and PC2 and perform a more extensive set of cleavages during the biosynthetic processing of POMC. To investigate the role of PC2 in the biosynthetic processing of POMC, AtT-20 mouse corticotropes were stably transfected with a full length PC2 cDNA. The AtT-20 cells expressing PC2 acquired the ability to perform all the additional cleavages seen in the intermediate pituitary, but did not acquire the ability to alpha-N-acetylate the product peptides. The kinetics of the earliest steps in biosynthetic processing were unaltered by the expression of PC2, and the changes due to PC2 expression were seen only in the middle and late steps in biosynthetic processing. Thus, both the identity of the final product peptides and the kinetics of the processing steps in the AtT-20 cells expressing PC2 fit the patterns expected for melanotropes of the intermediate pituitary.
Adrenocorticotropic Hormone↗
A dominant negative mutant of 2-5A-dependent RNase suppresses antiproliferative and antiviral effects of interferon.
2-5A-dependent RNase is the terminal factor in the interferon-regulated 2-5A system thought to function in both the molecular mechanism of interferon action and in the general control of RNA stability. However, direct evidence for specific functions of 2-5A-dependent RNase has been generally lacking. Therefore, we developed a strategy to block the 2-5A system using a truncated form of 2-5A-dependent RNase which retains 2-5A binding activity while lacking RNase activity. When the truncated RNase was stably expressed to high levels in murine cells, it prevented specific rRNA cleavage in response to 2-5A transfection and the cells were unresponsive to the antiviral activity of interferon alpha/beta for encephalomyocarditis virus. Remarkably, cells expressing the truncated RNase were also resistant to the antiproliferative activity of interferon. The truncated RNase is a dominant negative mutant that binds 2-5A and that may interfere with normal protein-protein interactions through nine ankyrin-like repeats.
3T3 Cells↗
Transport of BC1 RNA in hypothalamo-neurohypophyseal axons.
Ample evidence indicates that in nerve cells, several individual proteins are locally synthesized in postsynaptic domains in dendrites. By contrast, axonal terminals, at least in mammals, are generally thought to lack protein synthetic capacity. However, axonal nerve endings of the hypothalamo-neurohypophyseal tract have recently been shown to contain mRNAs encoding vasopressin, oxytocin, dynorphin, and neurofilament. In this report, we identify BC1 RNA, a small RNA polymerase III transcript that is specifically expressed in neurons, in hypothalamo-neurohypophyseal axons. BC1 RNA has previously been shown to be located in somatic and dendritic domains of various types of neurons in the rat nervous system. Here we present evidence to show that BC 1 RNA, like several neuropeptide mRNAs, is axonally transported from magnocellular hypothalamic neurons to neurosecretory nerve endings in the posterior pituitary. BC1 RNA, which has been reported to be a component of a ribonucleoprotein particle, is thus colocalized with dendritic mRNAs in dendritic domains and with axonal mRNAs in axonal domains, respectively. Such colocalization is indicative of functional interactions of BC1 RNA with those mRNAs that are targeted to extrasomatic domains of nerve cells.
Animals↗
[Morphology of right ventricle and hemodynamics in pulmonary atresia with intact ventricular septum].
Cardiac catheterization and angiography were performed in 31 patients with PA/IVS to evaluate the morphology of RV and hemodynamics. The age of patients ranged from 1 day to 39 month (mean 4.7 month). The patients were divided into three groups: mild (19.4%), moderate (64.5%) and severe (16.1%) RV hypoplasia, according to the degree of tricuspid valve and right ventricular hypoplasia. Seven of the 31 patients (22.6%) had right ventricular myocardial sinusoid-coronary artery fistula. The right and left ventricular pressures in 26 patients were measured simultaneously. The right ventricular pressures were supra-systemic in 18 patients (69.2%), systemic in 6 (23.1%), less than systemic pressures in 2 (7.7%); the others were PA/IVS with ASD(6 patients), PFO (25), PDA (25). Palliative and definitive operations were performed on 22 patients. The results show that determining the morphology of RV and the hemodynamics before operation is helpful in selecting appropriate operation for lowering the operative mortality.
Blood Pressure↗
Affinity blotting assay for 2-5A-dependent RNase.
The intracellular effectors known as 2-5A (ppp-(A2'p)nA) regulate the cleavage of single-stranded RNA by activating a latent endoribonuclease (2-5A-dependent RNase or RNase L). Accordingly this enzyme may exist in either an inactive form, free of 2-5A, or an active, 2-5A-bound form. Previously, a radiobinding assay for 2-5A-dependent RNase was developed that measured the amount of labeled ppp(A2'p)2A3'-[32P]Cp, a derivative of ppp(A2'p)nA, that bound the inactive enzyme form. Because 2-5A-dependent RNase has a particularly high affinity for 2-5A the radiobinding assay may not measure the 2-5A activated form of the enzyme. Therefore an efficient procedure to facilitate the detection of total 2-5A-dependent RNase (i.e., 2-5A-free and 2-5A-bound enzyme) in mouse spleen extracts was developed. Denaturing conditions were used to ensure that all 2-5A-dependent RNase was in the 2-5A-free form. After denaturation on polyacrylamide gel electrophoresis, optimal blotting conditions onto nitrocellulose and renaturation of the 2-5A binding site of 2-5A-dependent RNase were developed. This procedure allowed a population of enzyme that otherwise is not accessible by the classical radiobinding assay to be assayed, thus leading to an increased measurement of 15-17% in cytoplasmic spleen extracts.
Affinity Labels↗
Transport of ascorbic acid and dehydroascorbic acid by pancreatic islet cells from neonatal rats.
Several amidated biologically active peptides such as pancreastatin, thyrotropin-releasing hormone, pancreatic polypeptide and amylin are produced in endocrine pancreatic tissue which contains the enzyme necessary for their final processing, i.e. peptidylglycine alpha-amidating mono-oxygenase (EC 1.14.17.3). The enzyme needs ascorbic acid for activity as well as copper and molecular oxygen. The present work shows that pancreatic islet cells prepared from overnight cultures of isolated islets from 5-7-day-old rats accumulate 14C-labelled ascorbic acid by a Na(+)-dependent active transport mechanism which involves a saturable process (estimated Km 17.6 microM). Transport was inhibited by ouabain, phloridzin, cytochalasin B, amiloride and probenecid. Glucose inhibited or stimulated uptake, depending on the length of incubation time of the cells. The uptake of dehydroascorbic acid was linearly dependent on concentration. Dehydroascorbic acid was converted to ascorbic acid by an unknown mechanism after uptake. The uptake of both ascorbic acid and dehydroascorbic acid was inhibited by tri-iodothyronine, and uptake of ascorbic acid, but not of dehydroascorbic acid, was inhibited by glucocorticoids. Isolated secretory granules contained a fairly low concentration of iron but a high concentration of copper.
Animals↗
High ascorbic acid content in the rat endocrine pancreas.
The peptidyl alpha-amidation of biologically active peptides (a number of which are found in the endocrine pancreas) requires several co-factors, including ascorbic acid. In the present study, tissue contents and developmental changes of ascorbic acid in the rat endocrine pancreas were measured using a highly sensitive HPLC system. High concentrations were found in neonatal rats, with the highest value, 42.5 nmol/mg protein, in 2-day-old rats. The concentration decreased gradually with age to 19.4 nmol/mg in 5-week-old rats. The exocrine pancreas had a lower concentration, but a peak was also observed in 2-day-old rats. In freshly isolated islet cells, an intracellular concentration of 7.5 mmol/l was estimated in 5-7-day-old rats. Secretory granules isolated from 4-6-day-old rat islets contained 10.6 nmol/mg protein. Culturing islets or cells in ascorbic acid free medium resulted in a marked decrease in their contents. Ascorbic acid in secretory granules from such islets decreased at a relatively lower rate. Addition of ascorbic acid to cultured cells or islets reduced the loss markedly. Increasing the glucose concentration in islet culture medium in the presence of 100 mumols/l ascorbic acid increased the islet ascorbic acid concentration.
Aging↗
Rats with physically disconnected hypothalamo-pituitary tracts no longer contain vasopressin-oxytocin gene transcripts in the posterior pituitary lobe.
In rats, vasopressin- and oxytocin-encoding mRNAs are present in the posterior but absent in the anterior lobe of the pituitary gland. RNase protection experiments indicate that in the posterior pituitary and hypothalamus identical transcriptional start points are used. Furthermore, the two transcripts from posterior pituitary and hypothalamus show identical nucleotide sequences. Animals operated by paired electrical lesions in such a way that connections between the supraoptic nucleus (SON) and paraventricular nucleus (PVN) of the hypothalamus and the posterior pituitary lobe are destroyed continue to express the vasopressin and oxytocin gene in the hypothalamus but not in the posterior pituitary. Operated animals subjected to chronic intermittent salt loading for 6 days similarly contain vasopressin and oxytocin encoding transcripts in the hypothalamus but not in the posterior pituitary.
Animals↗
Evidence for presence of peptide alpha-amidating activity in pancreatic islets from newborn rats.
The peptide alpha-amidating activity of a homogenate of pancreatic islets from 5-7-day-old rats was investigated, using as substrate a glycine-extended tripeptide (D-Tyr-Val-Gly). The islet homogenates had a marked amidating activity, with a Km of 57 microM, a Vmax. of 185 pmol/h per mg and a pH optimum of 7.0. This activity was dependent on the presence of ascorbic acid (in the reduced form) and Cu2+, the optimum concentrations being 4 mM and 40 microM respectively. On fractionation of the homogenate, the highest specific activity was found in the soluble fraction. Exocrine pancreatic tissue showed very low levels of amidating activity.
Amino Acid Sequence↗
Uptake of ascorbic acid by freshly isolated cells and secretory granules from the intermediate lobe of ox hypophyses.
Mechanically isolated cells from the intermediate lobe of ox hypophyses contained 40.6 +/- 3.7 nmol mg-1 protein (mean +/- SE, n = 5) of ascorbic acid. They accumulated radioactivity time dependently, on incubation with L-[14C]ascorbic acid in ionic medium dominated by NaCl. No definite saturation of uptake occurred when mechanically isolated cells were incubated with increasing ascorbic acid concentrations up to 0.6 mM. But if such cells were purified on a Percoll gradient, a clear saturation of uptake could be observed. Acetylsalicylic acid reduced the uptake markedly. When cells loaded with L-[14C]ascorbic acid were homogenized and placed on a Percoll gradient, the radioactivity was recovered in several subcellular fractions. Decrease of the Na+ concentration or presence of ouabain in the medium did not cause noticeable changes in uptake by non-purified cells, whereas uptake by purified cells was clearly sodium-dependent. Phloridzin inhibited uptake. Secretory granules from pars intermedia contained 40.0 +/- 3.8 nmol mg-1 protein of ascorbic acid (mean +/- SE, n = 3) and could accumulate L-[14C]ascorbic acid rapidly in a KCl-dominated medium. The uptake was not saturable with ascorbic acid concentration and was not influenced by the presence of I mM ATP + I mM Mg2+ in the medium. The concentration of copper and iron in isolated cells was comparable to that in isolated neurohypophysial nerve terminals, whereas the concentration of zinc was considerably higher in the pars intermedia cells. The concentration of Cu, Zn, Fe and Co in secretory granules from pars intermedia was higher than in secretory granules from neurohypophyses.
Animals↗
Role of calmodulin in stimulus-secretion coupling.
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Animals↗
[Study on correction of abnormal fetal position by applying ginger paste at zhihying acupoint A. Report of 133 cases].
Applying fresh ginger paste at Zhihying acupoint before retiring, we treated 133 pregnant women (28 to 38 weeks' gestation) with breech position. There were 118 primigravidas. 238 untreated pregnant women (28 to 32 weeks' gestation) with breech position made up the control group. 113 out of the treated pregnant women had normal fetal position after treatment with 77.4% of correction rate. 48 out of the 113 pregnant women whose fetal position corrected by treatment only received once therapy, accounting for 42.5% of cured cases. Spontaneous correction of fetal position happened in 123 pregnant women of the control group with 51.6% of correction rate. There was a significant difference in the correction rate between study and control groups. (P less than 0.01), suggesting that this therapy is easy, economical, safe, and suitable to popularization at the basic level.
Acupuncture Points↗
[Congenital aortic coarctation in children treated by percutaneous transluminal balloon angioplasty (8 cases)].
Balloon angioplasty was performed in eight patients aged 3-12 years (mean 7.5) with coarctation of aorta (CoA). Seven children did not undergo operation before, while one patient had re-stenosis after surgical repair of the CoA. Immediately after angioplasty, the mean systolic pressure gradient was reduced from 7.8 +/- 2.8 to 1.7 +/- 1.1 kPa and the CoA diameter increased from 3.9 +/- 1.7 to 9.0 +/- 1.8 mm. Follow-up study of 2-18 months showed a continuing gradient decrease in seven of eight patients. No aneurysm was found in this series, probably related to the appropriate balloon size. Our data suggest that balloon angioplasty is a safe and effective method in relief of the stenosis by congenital membranous aortic coarctation and postoperative restenosis of the coarcted aorta.
Angioplasty, Balloon↗