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Beta thalassemia and translation of globin messenger RNA.

To define the quality and relative quantity of beta and alpha messenger RNA in human nonthalassemic and thalassemic reticulocytes, intact cells were incubated with [(35)S]methionine. The relative amounts of beta- and alpha-nascent chains on polysomes of different sizes were measured by tryptic digestion of pooled polysomes and by determination of the specific activities of beta and alpha peptides that contain methionine. Betachain synthesis predominated on heavy polysomes in nonthalassemic, as well as in thalassemic cells. Since beta chains in thalassemia are made on normal-size polyribosomes, we conclude that the defect in thalassemia does not involve reduction in the rate of initiation of translation due to the production of an abnormal beta message. Such would lead to beta-chain synthesis on very small polysomes. We therefore suggest that the decreased production of beta-globin chains results from a decreased amount of functional beta-globin messenger RNA.

Anemia, Hemolytic↗

Preparation of messenger RNA from mature skeletal and cardiac muscle.

Messenger RNA (poly(A) + RNA) has been prepared from mature skeletal muscle of adult rats by several procedures. These procedures involved oligodT-cellulose chromatography of either muscle polyribosomes (method 1), polysomal RNA isolated by CsCl gradient centrifugation of muscle polysomes (method 2), total muscle RNA isolated by CsCl gradient centrifugation (method 3), or total muscle RNA prepared by phenol extraction (method 4). Each procedure produced RNA in significant yields which sedimented in a broad band (from 4S to greater than 28S) on sodium dodecyl sulfate--sucrose gradients. In addition, poly (A) + RNA from each procedure stimulated protein synthesis in the wheat germ cell-free system. The best combination of yield and messenger activity was obtained for poly (A) + RNA prepared from polysomal RNA by method 2. This poly(A) + RNA preparation stimulated the cell-free synthesis of a number of presumptive myofibrillar proteins, including myosin heavy chain and actin, in the wheat germ system. The presence of the latter protein among the cell-free products was confirmed by DNase I affinity chromatography of appropriate reaction mixtures. Poly(A) + RNA was also isolated from rat cardiac muscle polysomal RNA by method 2. This RNA also directed the synthesis of myofibrillar proteins in the wheat germ system. The relative amounts of the proteins synthesized in the presence of skeletal and cardiac muscle poly(A) + RNA have been compared. The data indicate that the method described is suitable for the isolation of RNA with message activity from mature mammalian muscle.

Animals↗

In situ visualization of messenger RNA for basic fibroblast growth factor in living cells.

We examined whether messenger RNA for basic fibroblast growth factor (bFGF) could be visualized specifically by a fluorescent probe in living cells. A 15-nucleotide-long antisense or sense sequence for human bFGF was sandwiched between two complementary 5-nucleotide-long arm sequences. A fluorophore, 5-(2'-aminoethyl)aminonaphthalene-1-sulfonic acid (EDANS), was joined to the 5'-terminal phosphate, while 4-(4'-dimethylaminophenylazo)benzoic acid, quencher for EDANS, was joined to the 3'-terminal hydroxyl group. The probe emitted blue fluorescence only upon hybridization with the complementary 18-nucleotide-long sequence under ultraviolet light. The antisense or sense probe carried with liposome was delivered to human cells, trabecular cells of the eye, in a glass-bottom culture dish placed on the stage of an inverted microscope. Cells with the antisense probe did, but not with the sense probe, show blue fluorescence under ultraviolet light. The present study opens a way to measure the changing levels of a specific messenger RNA in living cells.

Base Sequence↗

Effects of haloperidol, clozapine and citalopram on messenger RNA levels of chromogranins A and B and secretogranin II in various regions of rat brain.

We have measured the messenger RNA levels of chromogranins A and B and secretogranin II in various brain regions of rats subchronically treated with various antipsychotic drugs. Since, as shown previously, the messenger RNA levels of these peptides are increased when neurons are stimulated, we hoped to identify by this approach those nuclei which are subchronically influenced by these drugs. The drugs chosen were the neuroleptic halperidol, a blocker of dopamine receptors, the atypical antipsychotic clozapine, which in addition to blocking dopamine receptors also blocks those for serotonin, and citalopram, a specific serotonin reuptake inhibitor. In agreement with previous data on neuropeptide messenger RNAs, we found in the dorsolateral striatum an increase of the secretogranin II messenger RNA levels after haloperidol and a much smaller one after clozapine. In the nucleus accumbens and in the bed nucleus of the stria terminalis, both compounds had a comparable positive effect. These differential effects can be attributed to a different action of these drugs on dopamine receptor subtypes. In the zona incerta, clozapine decreased the secretogranin II and chromogranin A message, whereas in the dorsal raphe it led to an increase. On the other hand, citalopram induced exactly the opposite effects in these two brain regions. This phenomenon can be explained by the differential interaction of these drugs with serotonergic mechanisms. Additional, relatively small changes of the mRNAs were seen in several other brain regions. These results establish that changes in the mRNA levels of the chromogranins are good indicators for the effect of drugs on certain brain nuclei. The concomitant action of haloperidol and clozapine on the limbic regions, i.e. the nucleus accumbens and the bed nucleus of the stria terminalis, points to these brain regions for the antipsychotic action of these two neuroleptics.

Animals↗

Regulation of psychostimulant-induced preprodynorphin, c-fos and zif/268 messenger RNA expression in the rat dorsal striatum by mu opioid receptor blockade.

Several studies have shown that psychostimulants can induce differential immediate early gene and neuropeptide expression in the patch versus matrix compartments of dorsal striatum. The patch compartment contains a high density of mu opioid receptors and activation of these receptors may contribute to psychostimulant-induced gene expression in the patch versus matrix compartments of dorsal striatum. However, the contribution of mu opioid receptor activation to psychostimulant-induced changes in gene expression in the patch compartment of dorsal striatum has not been examined. The current study examined the role of mu opioid receptors in psychostimulant induction of preprodynorphin, c-fos and zif/268 messenger RNA expression in the patch versus matrix compartments of dorsal striatum. Male Sprague-Dawley rats were treated with the mu opioid receptor antagonist, clocinnamox (1 mg/kg, s.c.), 24 h prior to treatment with cocaine (30 mg/kg, i.p.) or methamphetamine (15 mg/kg, s.c.) and sacrificed 45 min or 3 h later. Mu opioid receptor antagonism blocked psychostimulant-induced preprodynorphin messenger RNA expression only in the rostral patch compartment, whereas psychostimulant-induced zif/268 messenger RNA expression in the patch and matrix compartments was attenuated throughout the dorsal striatum. Clocinnamox pretreatment had no effect on stimulant-induced increases in c-fos expression. These data suggest that mu opioid receptor activation plays a specific role in psychostimulant-induced preprodynorphin messenger RNA expression in the rostral patch compartment and zif/268 messenger RNA expression throughout dorsal striatum.

Animals↗

Messenger RNA surveillance: neutralizing natural nonsense.

Messenger RNA transcripts that contain premature stop codons are degraded by a process termed nonsense-mediated mRNA decay (NMD). Although previously thought of as a pathway that rids the cell of non-functional mRNAs arising from mutations and processing errors, new research suggests a more general and evolutionarily important role for NMD in the control of gene expression.

Animals↗

Decreased expression of N-methyl-D-aspartate receptor 1 messenger RNA in select regions of Alzheimer brain.

An antisense oligonucleotide probe was used to examine the expression of gene encoding the obligatory NMDAR1 subunit of the N-methyl-D-aspartate receptor in the hippocampus and adjacent cortical areas (entorhinal and perirhinal cortices) of seven Alzheimer patients and in the same brain regions of seven control individuals. Both groups were matched according to age, sex, cause of death, post mortem delay, and tissue storage time. Densitometric analysis of in situ hybridization autoradiograms revealed a 34% (P<0.05) decrease in NMDAR1 messenger RNA levels in layer III of the entorhinal cortex in Alzheimer brains. Similar deficits. although statistically not significant, were observed in layers II and IV-VI of the entorhinal cortex, and in granule cells of the dentate gyrus. Reduced levels of NMDAR1 messenger RNA were also found in layers II-VI of the perirhinal cortex (41 53% decrease, P<0.02). There were no changes in NMDAR1 messenger RNA expression in the CA1, hilus, or subiculum. Both Alzheimer and control group show substantial intersubject variation in levels of NMDAR1 messenger RNA. The analysis of emulsion-dipped tissue revealed a trend toward a decrease in the number of silver grains overlying individual neurons in the CA1, entorhinal cortex, and granule cell layer of some Alzheimer patients. No significant relationship was detected between the levels of NMDAR1 messenger RNA and post mortem delay, tissue storage, age of the subjects, or mini mental state exam score either in control or Alzheimer individuals. In contrast, a strong inverse correlation between NMDAR1 expression and disease duration was found. These data suggest that reduction in expression of the NMDAR1 gene observed in certain regions of Alzheimer hippocampus and adjacent cortical regions is specific for the disease itself. We postulate that reduced transcript levels may reflect either regional cell loss or anomalies in glutamatergic input to the hippocampus and entorhinal cortex in Alzheimer's disease. When followed by changes at the receptor subunit protein level, altered expression of the NMDAR1 gene in Alzheimer brain may contribute, through the formation of N-methyl-D-aspartate receptors with different properties, to the previously reported modified N-methyl-D-aspartate receptor ligand binding, abnormal vulnerability of select neuronal populations to excitotoxic insult, and may also be involved in learning and memory deficits.

Aged↗

Alteration of expression levels of neuronal nitric oxide synthase and haem oxygenase-2 messenger RNA in the hippocampi and cortices of young adult and aged cognitively unimpaired and impaired Long-Evans rats.

Neuronal nitric oxide synthase and haem oxygenase-2 are postulated to be important enzymes involved in neuronal transmission and modulation of free radical levels in neurons. Hippocampal and cortical neuronal nitric oxide synthase and haem oxygenase-2 expressions were compared in young adult (6 months) and aged (24-26 months) Long-Evans rats. Aged rats were assigned as either cognitively unimpaired or impaired based on their performances in the Morris water maze behavioural task. In situ hybridization revealed increased neuronal nitric oxide synthase messenger RNA levels in selected regions of the hippocampi and cortices of aged rats. Moreover, aged cognitively impaired animals showed significantly higher neuronal nitric oxide synthase messenger RNA expression than aged cognitively unimpaired animals in several brain regions. For haem oxygenase-2 mRNA expressions, both young and aged cognitively impaired rats showed increased expressions in hippocampi compared with aged cognitively unimpaired rats, while no difference was found in cortices between all three animal groups. The increase in neuronal nitric oxide synthase messenger RNA expression levels in the aged animals may be related to increased free radical production occurring in ageing. Alternatively, elevated neuronal nitric oxide synthase and haem oxygenase-2 messenger RNA expressions may represent compensatory responses to oxidative stress and age-related changes in neuronal functions. Regarding cognitive status, aged cognitively impaired rats showed significant spatial memory deficits relative to young and aged cognitively unimpaired rats. Our data suggest a correlation between age-related cognitive impairment and change in messenger RNA expressions for the neuronal nitric oxide synthase and haem oxygenase-2 systems in brain areas implicated in learning and memory processes.

Aging↗

Antigen-specific messenger RNA for immunological research: purification and characterization of RNA from intestinal epithelial cells using specific antibody.

A murine organ-specific antigen system (ECAC B1,B2) has been described that is reactive with sera and lymphocytes from patients with chronic inflammatory bowel disease. However, the amino acid sequence of macromolecules comprising ECAC is unknown, making difficult synthesis of a genetic (DNA) probe for molecular biologic studies. As an alternative to obtain a specific cDNA clone, we developed a methodology to immuno-purify and characterize ECAC-specific messenger RNA from murine and human gut mucosal epithelium. Advantages of this new approach include that it is rapid, non-radioactive, applicable to heterologous or monoclonal immunoglobulin, and of low cost. 100 X 10(6) intestinal epithelial cells were lysed with 0.35% V/V NP-40, and the supernatant layered on a 65% W/V sucrose solution for isolation of polyribosomes by ultracentrifugation. ECAC B1/B2-specific mRNA was isolated from this polyribosome fraction using protein A column-purified specific immunoglobulin from heterologous hyperimmune serum or from monoclonal ascites, followed by adsorption of antibody-bound polyribosomes on a solid phase composed of Sepharose-protein A. After messenger RNA elution, the poly-adenine-containing fraction was further purified by oligo-dT chromatography and characterized. The yield of highly purified messenger RNA (A260/A280 greater than or equal to 2) was 10-20 micrograms/10(8) epithelial cells, and formaldehyde agarose gel electrophoresis demonstrated a limited number of RNA bands had been isolated (150-1400 base-pairs in size). The function of murine and human (normal and disease-involved) messenger RNA isolates was determined in a cell-free in vitro translation system, demonstrating synthesis of single components of ECAC identified by immunoblotting, enzyme-linked immuno-sorbent assay, and analytical polyacrylamide gel electrophoresis of lysate fractions after immuno-affinity chromatography. We conclude that heterologous or monoclonal antibody can be used to isolate antigen-specific messenger RNA from a species other than that from which the antigen was originally isolated, that the functional status for translation of newly purified mRNA can be easily determined by one of several non-radioactive means, and that the technique can be applied even to cells with a high enzymatic degradative capacity, such as those in gut epithelium.

Animals↗

Differential hippocampal expression of glutamic acid decarboxylase 65 and 67 messenger RNA in bipolar disorder and schizophrenia.

BACKGROUND: Expression of messenger RNA (mRNA) for the gamma-aminobutyric acid (GABA)-synthesizing enzyme, glutamic acid decarboxylase (GAD), in the prefrontal cortex and the number of GABAergic neurons in the hippocampus are reduced in schizophrenia and bipolar disorder. We tested the hypothesis that the expression of the 2 isoforms, one 65 kd (GAD(65)) and the other 67 kd (GAD(67)), is differentially affected in the hippocampus in schizophrenia and bipolar disorder. METHODS: Hippocampal sections from 15 subjects in 3 groups (control subjects and subjects with schizophrenia and bipolar disorder) were studied using an in situ hybridization protocol with sulfur 35-labeled complementary riboprobes for GAD(65) and GAD(67) mRNA. Emulsion-dipped slides were analyzed for the density of GAD mRNA-positive neurons in 4 sectors of the hippocampus and for the cellular expression level of both GAD mRNAs. RESULTS: The density of GAD(65) and GAD(67) mRNA-positive neurons was decreased by 45% and 43%, respectively, in subjects with bipolar disorder, but only 14% and 4%, respectively, in subjects with schizophrenia. The decreased density of GAD(65) mRNA-positive neurons in subjects with bipolar disorder was significant in sectors CA2/3 and dentate gyrus, and that of GAD(67) mRNA-positive neurons was significant in CA4, but not other hippocampal sectors. Cellular GAD(65) mRNA expression was significantly decreased in subjects with bipolar disorder, particularly in CA4, but not in schizophrenic subjects. Cellular GAD(67) mRNA expression was normal in both groups. CONCLUSION: We have found a region-specific deficit of GAD(65) and GAD(67) mRNA expression in bipolar disorder.

Adult↗

Identification of messenger RNA for glutamate dehydrogenase using a spectrophotometric probe.

Specific messenger RNA for glutamate dehydrogenase was partially purified from a calf liver polysomal poly(A)-mRNA fraction by sucrose density gradient centrifugation. Enzyme activity in the translational incubation mixture was detected by measuring NADH oxidation in the presence of alpha-ketoglutarate and ammonia as a decrease in absorbency 340-442 nm in a dual wavelength Aminco DW-2 spectrophotometer.

Animals↗

Effect of beta-adrenoceptor antagonist and angiotensin-converting enzyme inhibitor on hypertension-associated changes in adenylyl cyclase type V messenger RNA expression in spontaneously hypertensive rats.

Adenylyl cyclase (AC) messenger RNA (mRNA) expression is decreased in failing hearts. Diminished expressions are accompanied by desensitization of beta-adrenergic signal transduction. Factors contributing to such changes in mRNA expression for the major myocardial isoform AC V are not well established. To assess the contributions of hypertension, left ventricular hypertrophy (LVH), the renin-angiotensin-aldosterone system (RAS), and the sympathetic nervous system to these changes, ventricular expression of AC V mRNA was measured at different ages in spontaneously hypertensive rats (SHRs). In addition, the effects on them of angiotensin-converting enzyme inhibitor and beta-adrenoceptor antagonists were determined. Prior to quantitative Northern blotting at ages 5, 9, or 12 weeks, hemodynamic and morphologic variables were measured in SHRs and Wistar-Kyoto rats (WKYs). The SHRs and WKYs were treated with an angiotensin-converting enzyme inhibitor, enalapril (10 mg/kg/d), or a beta(1)-adrenoceptor antagonist, atenolol (100 mg/kg/d), for 8 weeks preceding Northern analysis. Myocardial AC V mRNA expression increased from 5-12 weeks in both SHRs and WKYs. Expression of AC V mRNA in SHRs increased somewhat less than in WKYs at 9 weeks and significantly less at 12 weeks. This was accompanied by development of LVH and hypertension in SHRs. Blood pressure and left ventricular weight relative to body weight were markedly decreased by enalapril and were moderately decreased by atenolol. Expression of AC V mRNA in SHRs at 12 weeks was normalized equally by enalapril and atenolol to the level of WKYs. Thus AC V mRNA expression increases are blunted in the early stages of LVH in SHRs under the influences of beta(1)-adrenergic signal transduction and the RAS.

Adenylyl Cyclases↗

The apolipoprotein B messenger RNA editing enzyme.

The editing of apolipoprotein (apo)B messenger RNA (mRNA) involves a novel C to U modification, which creates an in-frame stop-translation codon, thereby generating the carboxyl-terminal of apoB48. The 27 kDa catalytic subunit of the editing enzyme has been cloned and established to be a zinc-containing cytidine deaminase. The catalytic subunit is guided to the editing site by a second targeting subunit or subunits. A candidate for the targeting subunit is a 60 kDa protein that can be UV crosslinked to the sequence UGAU, which is part of a motif downstream of the editing site that is essential for editing.

Amino Acid Sequence↗

Translational potentiation of messenger RNA with secondary structure in Xenopus.

Differential translation of messenger RNA (mRNA) with stable secondary structure in the 5' untranslated leader may contribute to the dramatic changes in protein synthetic patterns that occur during oogenesis and early development. Plasmids that contained the bacterial gene chloramphenicol acetyltransferase and which encoded mRNA with (hpCAT) or without (CAT) a stable hairpin secondary structure in the 5' noncoding region were transcribed in vitro, and the resulting mRNAs were injected into Xenopus oocytes, eggs, and early embryos. During early oogenesis, hpCAT mRNA was translated at less than 3 percent of the efficiency of CAT mRNA. The relative translational potential of hpCAT reached 100 percent in the newly fertilized egg and returned to approximately 3 percent after the midblastula transition.

Animals↗

Vaccination with messenger RNA.

As an alternative to DNA-based vaccines, messenger RNA (mRNA)-based vaccines present additional safety features: no persistence, no integration in the genome, no induction of autoantibodies. Moreover, mRNA which are generated by in vitro transcription, are easy to produce in large amounts and very high purity. This feature facilitates the good manufacturing practices process and guaranties batch-to-batch reproducibility. Vaccination can be achieved by several delivery methods including direct injection of naked mRNA, injection of mRNA encapsulated in liposomes Gene Gun delivery of mRNA loaded on gold beads or in vitro transfection of the mRNA in cells followed by re-injection of the cells into the patients. Two of these technologies are being evaluated in human clinical trials: (1) in vitro mRNA-transfection of dendritic cells to be adoptively transferred and (2) direct injection of globin-stabilized mRNA. This chapter describes the production of mRNA and the preparation of the two types of mRNA-based vaccines tested in humans.

Adoptive Transfer↗

Reduction of zif268 messenger RNA expression during prolonged withdrawal following "binge" cocaine self-administration in rats.

Cocaine self-administration increases dopamine efflux and neuronal activity in the mesocorticolimbic dopamine system compared with experimenter-administered cocaine. Following a prolonged cocaine self-administration binge, dopamine efflux in the nucleus accumbens is attenuated and behaviors emerge that are indicative of anhedonia and anxiety. The neuronal correlates of these behavioral and neurochemical effects of a cocaine binge were assessed using in situ hybridization histochemistry to detect changes in zif268 messenger RNA expression. Rats were fitted with intravenous catheters; one group was trained to self-administer cocaine (0.5mg/injection), then allowed continuous access to cocaine during a 16h binge, while yoked animals received either saline or cocaine according to the same schedule. Measurement of tactile startle responses and ultrasonic distress calls either immediately after termination of cocaine access or one or 14 days later confirmed peak withdrawal at 24h after the binge. The level of zif268 messenger RNA was lower upon termination of cocaine self-administration than in both yoked treatment groups in the ventral tegmental area and hippocampus. In contrast, zif268 messenger RNA expression increased in the periaqueductal gray matter one day after termination of passive cocaine treatment, coincident with enhanced expression of ultrasonic vocalizations. Zif268 messenger RNA expression decreased over time in the nucleus accumbens core and infralimbic cortex, with reduced expression observed in the nucleus accumbens core, caudatoputamen, hippocampus and amygdala 14 days after termination of cocaine self-administration. The results suggest that withdrawal following a cocaine self-administration binge produces a long-lasting reduction of constitutive zif268 messenger RNA expression in mesocorticolimbic brain regions related to the nucleus accumbens. The relatively greater effect in animals that self-administered cocaine implies a relationship of certain regional responses to behavioral conditioning.

Animals↗

Breakdown of rat-liver ergosomes in vivo after actinomycin inhibition of messenger RNA synthesis.

Ribosomes isolated from rat liver occur predominantly in the form of aggregates (ergosomes) corresponding to multiples of 73S particles held together by messenger RNA. After injecting rats with actinomycin, these aggregates gradually break down in vivo to 73S monomers and 113S dimers. We conclude that the observed breakdown results from the degradation of messenger RNA and the prevention by actinomycin of the synthesis of new messenger RNA.

Animals↗

Localization of insulin-like growth factor binding protein-2 messenger RNA during postnatal brain development: correlation with insulin-like growth factors I and II.

Insulin-like growth factor binding protein-2 binds insulin-like growth factors I and II with high affinity and modulates the interaction of these ligands with the type I insulin-like growth factor receptor. Previously we have shown that insulin-like growth factor binding protein-2 and insulin-like growth factor-I gene expression are spatiotemporally co-ordinated in the developing retina and cerebellum. The present study examined other brain regions and found a similar correlation in insulin-like growth factor binding protein-2 and insulin-like growth factor-I gene expression in relay stations of developing sensory and cerebellar networks of the rat. In these sites, as in the cerebellum and retina, insulin-like growth factor-I messenger RNA is localized in the principal or projection neurons and insulin-like growth factor binding protein-2 messenger RNA is localized in surrounding astroglia. Outside these sensory relay centers, the relationship of insulin-like growth factor binding protein-2 to insulin-like growth factor-I gene expression is not so well defined. In the hippocampal formation, insulin-like growth factor-I messenger RNA is present in large interneurons and insulin-like growth factor binding protein-2 messenger RNA in regional astrocytes; their timing is co-ordinated, with peak levels seen about postnatal day 12, but their anatomical association is not apparent. The least degree of correlation between local insulin-like growth factor-I and insulin-like growth factor binding protein-2 gene expression is found in the neocortex, where insulin-like growth factor-I is abundant in scattered large neurons from postnatal days 3 to 20. In contrast, insulin-like growth factor binding protein-2 messenger RNA is widely expressed throughout the neocortex from before birth to about postnatal day 12, in a pattern consistent with expression by nascent astroglia. Insulin-like growth factor binding protein-2 gene expression is greatly reduced throughout the brain by the third week after birth; in response to optic nerve transection, however, there is a resurgence of gene expression for this factor by activated astrocytes in affected retinal target regions. Insulin-like growth factor binding protein-2 and insulin-like growth factor-II messenger RNAs are co-localized in the choroid plexus and leptomeninges from the time of birth onward without diminution. In summary, insulin-like growth factor binding protein-2 demonstrates complex patterns of gene expression during postnatal brain development--some of which appear to be closely related to local insulin-like growth factor synthesis and some of which appear independent of it.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗