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5HT1B and 5HT1D receptor mRNA differential co-localization with peptide mRNA in the guinea pig trigeminal ganglion.

To investigate the possible role of 5HT1B and/or 5HT1D receptors in controlling neurogenic inflammation, we performed a co-localization study of the mRNA for 5HT1B and 5HT1D receptors and of substance P or calcitonin gene-related peptide (CGRP) mRNA in the guinea pig trigeminal ganglion using double labelling in situ hybridization techniques. The 5HT1D receptor mRNA is abundant whereas 5HT1B receptor mRNA is scarce. The vast majority of cells containing substance P mRNA also contained 5HT1B receptor mRNA, but very few cells expressed substance P mRNA and 5HT1D receptor mRNA. Both receptor mRNAs were co-localized with CGRP mRNA. Hence, 5HT1D receptors may control the release of CGRP only, whereas 5HT1B receptors may control the release of both substance P and CGRP. The question remains whether selective 5HT1D agonists will have migraine abortive properties.

Animals↗

Nucleocytoplasmic transport of fluorescent mRNA in living mammalian cells: nuclear mRNA export is coupled to ongoing gene transcription.

In eukaryotic cells, export of mRNA from the nucleus to the cytoplasm is one of the essential steps in gene expression. To examine mechanisms involved in the nucleocytoplasmic transport of mRNA, we microinjected fluorescently labeled fushi tarazu (ftz) pre-mRNA into the nuclei of HeLa cells. The injected intron-containing ftz pre-mRNA was distributed to the SC35 speckles and exported to the cytoplasm after splicing by an energy-requiring active process. In contrast, the injected intron-less ftz mRNA was diffusely distributed in the nucleus and then presumably degraded. Interestingly, export of the ftz pre-mRNA was inhibited by treatment with transcriptional inhibitors (actinomycin D, alpha-amanitin or DRB). Cells treated with transcriptional inhibitor showed foci enriched with the injected mRNA, which localize side by side with SC35 speckles. Those nuclear foci, referred to as TIDRs (transcriptional-inactivation dependent RNA domain), do not overlap with paraspeckles. In addition, in situ hybridization analysis revealed that the export of endogenous poly(A)+ mRNA is also affected by transcriptional inactivation. These results suggest that nuclear mRNA export is coupled to ongoing gene transcription in mammalian cells.

Active Transport, Cell Nucleus↗

Energy requirement and kinetics of transport of poly(A)-free histone mRNA compared to poly(A)-rich mRNA from isolated L-cell nuclei.

ATP-promoted efflux of poly(A)-rich RNA from isolated nuclei of prelabeled mouse lymphoma L5178y cells has an activation energy of 51.5 kJ/mol, similar to that found for the nuclear envelope nucleoside triphosphatase (48.1 kJ/mol) assumed to be involved in mediating nucleocytoplasmic transport of at least some RNA. Here we show that efflux of two specific poly(A)-rich mRNAs (actin and beta-tubulin) from isolated L-cell nuclei is almost totally dependent on the presence of ATP, while efflux of poly(A)-free histone mRNA (H4, H2B, and H1) also occurs to a marked extent in the absence of this nucleotide. Measurements of temperature dependence of transport rate revealed an activation energy of 56.1 kJ/mol for actin mRNA, while the activation energy for histone-H4-mRNA efflux was in the same range as that found for ATP-induced release of RNA from demembranated nuclei (about 15-20 kJ/mol). Addition of nonhydrolyzable nucleotide analogs of ATP to the in vitro system used for measurement of RNA transport did not result in release of nonhistone mRNA (actin), but enhanced the efflux of H4 mRNA to approximately the same extent as ATP. Although not absolutely required, addition of ATP stimulated the rate of export of histone mRNA about twofold. Only the poly(A)-rich RNA, but not the poly(A)-free RNA, released from isolated nuclei was found to compete with poly(A) for the nuclear envelope mRNA-binding site, indicating the mechanism of transport for both RNA classes to be distinct. Export of both nonhistone and histone mRNA was found to be inhibited by a monoclonal antibody against a p60 nuclear-pore-complex antigen. This antibody had no effect on the nucleoside triphosphatase, mediating transport of poly(A)-rich mRNA.

Animals↗

Control of the translational efficiency of beta-F1-ATPase mRNA depends on the regulation of a protein that binds the 3' untranslated region of the mRNA.

The expression of the nucleus-encoded beta-F1-ATPase gene of oxidative phosphorylation is developmentally regulated in the liver at both the transcriptional and posttranscriptional levels. In this study we have analyzed the potential mechanisms that control the cytoplasmic expression of beta-F1-ATPase mRNA during liver development. Remarkably, a full-length 3' untranslated region (UTR) of the transcript is required for its efficient in vitro translation. When the 3' UTR of beta-F1-ATPase mRNA is placed downstream of a reporter construct, it functions as a translational enhancer. In vitro translation experiments with full-length beta-F1-ATPase mRNA and with a chimeric reporter construct containing the 3' UTR of beta-F1-ATPase mRNA suggested the existence of an inhibitor of beta-F1-ATPase mRNA translation in the fetal liver. Electrophoretic mobility shift assays and UV cross-linking experiments allowed the identification of an acutely regulated protein (3'betaFBP) of the liver that binds at the 3' UTR of beta-F1-ATPase mRNA. The developmental profile of 3'betaFBP parallels the reported changes in the translational efficiency of beta-F1-ATPase mRNA during development. Fractionation of fetal liver extracts revealed that the inhibitory activity of beta-F1-ATPase mRNA translation cofractionates with 3'-UTR band-shifting activity. Compared to other tissues of the adult rat, kidney and spleen extracts showed very high expression levels of 3'betaFBP. Translation of beta-F1-ATPase mRNA in the presence of kidney and spleen extracts further supported a translational inhibitory role for 3'betaFBP. Mapping experiments and a deletion mutant of the 3' UTR revealed that the cis-acting element for binding 3'betaFBP is located within a highly conserved region of the 3' UTR of mammalian beta-F1-ATPase mRNAs. Overall, we have identified a mechanism of translational control that regulates the rapid postnatal differentiation of liver mitochondria.

ADP-Ribosylation Factors↗

An mRNA stability complex functions with poly(A)-binding protein to stabilize mRNA in vitro.

The stable globin mRNAs provide an ideal system for studying the mechanism governing mammalian mRNA turnover. alpha-Globin mRNA stability is dictated by sequences in the 3' untranslated region (3'UTR) which form a specific ribonucleoprotein complex (alpha-complex) whose presence correlates with mRNA stability. One of the major protein components within this complex is a family of two polycytidylate-binding proteins, alphaCP1 and alphaCP2. Using an in vitro-transcribed and polyadenylated alpha-globin 3'UTR, we have devised an in vitro mRNA decay assay which reproduces the alpha-complex-dependent mRNA stability observed in cells. Incubation of the RNA with erythroleukemia K562 cytosolic extract results in deadenylation with distinct intermediates containing a periodicity of approximately 30 nucleotides, which is consistent with the binding of poly(A)-binding protein (PABP) monomers. Disruption of the alpha-complex by sequestration of alphaCP1 and alphaCP2 enhances deadenylation and decay of the mRNA, while reconstitution of the alpha-complex stabilizes the mRNA. Similarly, PABP is also essential for the stability of mRNA in vitro, since rapid deadenylation resulted upon its depletion. An RNA-dependent interaction between alphaCP1 and alphaCP2 with PABP suggests that the alpha-complex can directly interact with PABP. Therefore, the alpha-complex is an mRNA stability complex in vitro which could function at least in part by interacting with PABP.

3' Untranslated Regions↗

Germin. Molecular cloning of cDNA that selects germin mRNA from bulk wheat mRNA.

(1) Bulk mRNA from germinated wheat embryos was denatured with methylmercury and subjected to electrophoresis in agarose gel to obtain a fraction of mRNA that was modestly enriched with respect to its complement of translatable germin mRNA. This fraction of mRNA was used as a source of primary templates for preparing a cDNA library. (2) Escherichia coli JM101 was transfected with recombinant pUC8 plasmids containing cDNA inserts. Colonies of transformed bacteria (ca. 4 x 10(3)) were differentially screened by hybridizing them with cDNA probes that were prepared from RNA populations containing different proportions of translatable germin mRNA. (3) A 160 base pair (bp) cDNA, which hybridized more strongly to the probe made from the RNA population containing the greater proportion of translatable germin mRNA in colony hybridizations, also hybridized more strongly to the RNA population containing the greater proportion of translatable germin mRNA when it was used as a probe for Northern analysis. (4) As judged by peptide mapping of a protein made by cell-free translation, the 160-bp cDNA selected virtually pure germin mRNA from the bulk mRNA of germinated wheat embryos when it was used in "hybrid release" experiments. The same 160-bp cDNA was used to select a "full length" germin cDNA from a library prepared by the Gubler-Hoffman method.

Cloning, Molecular↗

Cx32 mRNA in rat liver: effects of inflammation on poly(A) tail distribution and mRNA degradation.

Previous studies showed that the expression of connexin 32 (Cx32), the polypeptide subunit component of the major hepatic gap junction, is reduced in liver by changes in mRNA stability during bacterial lipopolysaccharide (LPS)-induced inflammation. In this study, we examined the distribution of Cx32 mRNA poly(A) tail lengths during LPS-induced inflammation, because this is considered the first step in the degradation of many mRNAs. During LPS treatment the first detectable change in Cx32 mRNA was a gradual shortening of its poly(A) tail, which reached a final size of approximately 20 nucleotides. However, the poly(A) tail did not disappear entirely before the bulk of Cx32 mRNA was degraded. Treatment with actinomycin D, which blocks the degradation of Cx32 mRNA after LPS administration, resulted in the appearance of a completely deadenylated mRNA, which otherwise could not be detected. On the contrary, treatment with cycloheximide resulted in a decrease in the stability of Cx32 mRNA without an apparent change of the poly(A) tail size. The effect of cycloheximide on Cx32 mRNA stability seems to be due indirectly to the induction of an inflammatory response by this drug. These results suggest that, similar for many mRNAs, shortening of the poly(A) tail is one of the first steps in the degradation of Cx32 mRNA during inflammation.

Amino Acid Sequence↗

Cytochrome c mRNA and alpha-actin mRNA in muscles of rats fed beta-GPA.

A diet of 1% beta-guanidinopropionic acid (beta-GPA) fed to rats for weeks results in decreased muscle adenosine triphosphate and creatine phosphate concentrations (J. Biol. Chem. 249: 1060-1063, 1974), increased activities of selected mitochondrial enzymes (Biochem. J. 232: 125-131, 1985), and atrophied type IIb fibers (Lab. Invest. 33: 151-158, 1975). The hypothesis of the present study was that chronic beta-GPA feeding would increase cytochrome c mRNA in muscle and would decrease alpha-skeletal actin mRNA in type IIb muscle. Data collected supported, in part, the hypothesis. After 22 days of a 1% beta-GPA diet, cytochrome c mRNA was increased 60-67% in muscles with inherently low cytochrome c mRNA but was not altered in muscles with higher cytochrome c mRNA levels. alpha-Skeletal actin mRNA was unchanged in muscles with low and high cytochrome c mRNA after 22 days of 1% beta-GPA. After 66 days of beta-GPA feeding, both cytochrome c mRNA and alpha-skeletal actin mRNA were decreased 18 and 26%, respectively, per unit of total RNA, in white quadriceps muscle. At the same time muscles composed of predominantly type II fibers atrophied 22%, whereas type I muscle size was unaltered. These data suggest that high-energy phosphate levels could play some role in adaptive changes in muscle composition.

Actins↗

Tissue distribution and regulation of insulin-like growth factor (IGF)-binding protein-3 messenger ribonucleic acid (mRNA) in the rat: comparison with IGF-I mRNA expression.

Insulin-like growth factor-binding protein-3 (IGFBP-3) is the most abundant IGFBP in rat and human sera. The present study demonstrates the expression of the rat IGFBP-3 gene in a large number of tissues and coexpression, but not necessarily equal expression, with IGF-I mRNA. Tissues with a major abundance of IGFBP-3 were kidney, antrum of stomach, placenta, uterus, and liver. Changes in hepatic and renal levels of IGFBP-3 mRNA were analyzed after hypophysectomy (with and without GH treatment) and in the developing postnatal rat. These results were compared to changes in IGF-I mRNA levels under the same physiological conditions. Using S1 nuclease analysis, IGFBP-3 mRNA was present in the kidney and liver of 1-day-old rats and rose significantly in both organs by week 1. Thereafter, levels remained relatively constant, particularly in the liver. This is in marked contrast to the hepatic IGF-I pattern, which showed a continual rise up to 8 weeks. Hepatic IGFBP-3 gene expression was partially GH dependent, with IGFBP-3 mRNA levels falling (approximately 50%) after hypophysectomy and rising slightly after GH treatment. These changes were much less dramatic than those in IGF-I mRNA. In contrast, the renal levels of IGFBP-3 mRNA increased after hypophysectomy, (approximately 100%), but did not decrease with GH treatment. These data suggest that IGFBP-3 mRNA abundance is regulated differently in different tissues, and in at least some tissues is less sensitive to regulation than is IGF-I mRNA.

Animals↗

Paradoxical responses of hypothalamic corticotropin-releasing factor (CRF) messenger ribonucleic acid (mRNA) and CRF-41 peptide and adenohypophysial proopiomelanocortin mRNA during chronic inflammatory stress.

We have determined the time course of the neuroendocrine response of Piebald-Viral-Glaxo (PVG) rats during the development of mycobacterially induced adjuvant arthritis. Anterior pituitary POMC mRNA increased at the time of onset of mycobacterially induced arthritis, but, paradoxically, coincident with the first signs of arthritis there was a consistent fall in CRF mRNA in the hypothalamic paraventricular nucleus. Coincident with this fall in CRF message, there was a corresponding decrease in CRF-41 peptide release into the hypophysial portal blood (HPB). In contrast, however, vasopressin release into the HPB was increased. There was an increase in adrenal weight associated with the development of arthritis, reflecting chronic activation of the HPA axis, which was reflected by increased circulating corticosterone concentrations. The synthetic adjuvant CP20961, which has different antigenic determinants, also caused an increase in POMC mRNA in the anterior pituitary, a decrease in CRF mRNA in the hypothalamic paraventricular nucleus, and a decrease in CRF-41 peptide release into the HPB in PVG rats 28 days after the induction of the arthritis. The arginine vasopressin level was not significantly different from the control value. In Sprague-Dawley rats, mycobacterial adjuvant resulted in a similar increase in POMC mRNA in the anterior pituitary 28 days after injection of the adjuvant. In this strain of rat there was no corresponding change in CRF mRNA. While there are some strain differences in the degree of change in CRF mRNA, both strains showed a common paradox of a marked increase in adenohypophyseal POMC mRNA not associated with increased CRF mRNA or peptide release. In the PVG strain of rat, CRF actually appears to be inhibited. The mechanisms involved in this disparity are unclear.

Adrenal Cortex Hormones↗

The poly(A)-limiting element enhances mRNA accumulation by increasing the efficiency of pre-mRNA 3' processing.

The poly(A)-limiting element (PLE) is a conserved sequence originally found in the 3' UTR of Xenopus albumin mRNA whose presence restricts the length of the poly(A) tail on both pre-mRNA and fully processed mRNA to <20 nt. Results presented in this study show that the PLE also increases the cytoplasmic level of reporter beta-globin mRNA. Transcription run-on shows this increase was not due to increased reporter gene transcription, and experiments with tetracycline repressor-controlled reporter mRNA showed the PLE does not alter the rate of mRNA decay. Both RT-PCR and RNase protection assay showed the PLE caused a 50% increase in the 3' processing of reporter beta-globin mRNA in vivo. This was confirmed in vitro, where PLE-containing RNA was cleaved in HeLa nuclear extract at a rate 80% faster than a control RNA bearing an inactive element. These results indicate that the PLE regulates the length of the poly(A) tail and the efficiency of 3' processing. In addition, they show that PLE-containing mRNA with a <20-nt poly(A) tail is as stable as mRNA with a 100- to 200-nt poly(A) tail.

3' Untranslated Regions↗

Nascent-peptide-mediated ribosome stalling at a stop codon induces mRNA cleavage resulting in nonstop mRNA that is recognized by tmRNA.

Recent studies have established that tmRNA-mediated protein tagging occurs at stop codons depending on the C-terminal amino acid sequence of the nascent polypeptide immediately adjacent to those codons. We investigate here how the trans-translation at a stop codon occurs by using model crp genes encoding variants of cAMP receptor protein (CRP). We demonstrate that a truncated crp mRNA is efficiently produced along with a normal transcript from the model gene where tmRNA-mediated protein tagging occurs. The truncated crp mRNA was not detected in the presence of tmRNA, indicating that its degradation was facilitated by tmRNA. The major 3'-ends of the truncated crp mRNA in cells unable to express tmRNA were mapped at and near the stop codon. When RNA derived from the model crp-crr fusion gene was analyzed, crr mRNA was detected as a downstream cleavage product along with the upstream crp mRNA. These results are compatible with the hypothesis that ribosome stalling caused by the tagging-provoking sequences leads to endonucleolytic cleavage of mRNA around the stop codon, resulting in nonstop mRNA. In addition, the data are consistent with the view that mRNA cleavage is the cause of trans-translation at stop codons. Neither the bacterial toxin RelE nor the known major endoribonucleases are required for this cleavage, indicating that either other endoribonuclease(s) or the ribosome itself would be responsible for the mRNA cleavage in response to ribosome stalling caused by the particular nascent peptides.

Bacterial Toxins↗

Reduction in circulating IGF-I and hepatic IGF-I mRNA levels after caecal ligation and puncture are associated with differential regulation of hepatic IGF-binding protein-1, -2 and -3 mRNA levels.

Sepsis is characterized by a severe shift in metabolism, characterized by low IGF-I levels. We have studied the influence of caecal ligation and puncture (CLP) on the levels of circulating IGF-I and hepatic IGF-I and IGF-binding protein (IGFBP)-1, -2 and -3 mRNA in adult male Wistar rats (n = 12) and compared it with sham-operated rats (n = 6). In order to exclude anorexia-induced changes we also studied animals pair-fed to both groups. IGF-I levels were measured by RIA. Steady-state hepatic IGF-I, IGFBP-1, IGFBP-2 and IGFBP-3 mRNA levels were measured by Northern blot analysis using specific rat cDNA probes. Food intake averaged 13.0 +/- 2.0 g/day in the sham-operated rats fed ad libitum during the study period, with a sharp decline in food intake in the CLP animals (2.3 +/- 1.3 g/day). After CLP, there was a significant reduction in circulating IGF-I levels (467.2 +/- 50.9 micrograms/l) compared with sham-operated animals (924.0 +/- 75.3 micrograms/l; P = 0.04) or those pair-fed to the CLP rats (612.5 +/- 52.9 micrograms/l; P = 0.04). Total hepatic IGF-I mRNA levels were significantly reduced (2.57 +/- 0.05 densitometric units (DU) after CLP compared with the sham-operated group (2.71 +/- 0.04); P = 0.04), or their pair-fed controls (2.75 +/- 0.08 DU; P < 0.05). Hepatic IGFBP-3 mRNA levels were lower after CLP (0.37 +/- 0.04 DU) than in the sham-operated animals (0.66 +/- 0.09 DU; P = 0.04) or their pair-fed controls (0.61 +/- 0.05 DU; P = 0.04). On the other hand, hepatic IGFBP-2 mRNA levels were increased after CLP (0.91 +/- 0.11 DU) compared with sham-operated animals (0.28 +/- 0.06 DU; P = 0.01) or with their pair-fed controls (0.22 +/- 0.02; P = 0.01), as were hepatic IGFBP-1 mRNA levels (CLP animals 0.95 +/- 0.11 DU; sham-operated 0.30 +/- 0.04 DU, P = 0.01; pair-fed 0.30 +/- 0.02 DU, P = 0.01). No significant difference between sham-operated animals and their pair-fed controls was observed in circulating IGF-I levels (888.0 +/- 109.3 micrograms/l; P = not significant (N.S.)), hepatic mRNA levels for IGF-I (2.72 +/- 0.06 DU; P = N.S), IGFBP-3 (0.71 +/- 0.07 DU; P = N.S.), IGFBP-2 (0.25 +/- 0.07 DU; P = N.S.) or IGFBP-1 (0.27 +/- 0.06 DU; P = N.S.). In summary, after CLP there was a reduction in both circulating and hepatic IGF-I mRNA levels associated with a specific and differential regulation of hepatic IGFBP-1, -2 and -3 mRNA levels. Although we cannot eliminate a possible effect of surgical stress combined with malnutrition, our results suggest that these changes are a specific effect of sepsis rather than simply a result of surgical stress or poor nutrition alone.

Animals↗

Diazepam-binding inhibitor/acyl-CoA-binding protein mRNA and peripheral benzodiazepine receptor mRNA in endocrine and immune tissues after prenatal diazepam exposure of male and female rats.

Peripheral benzodiazepine (BDZ) receptor (PBR) and diazepam-binding inhibitor/acyl-CoA-binding protein (DBI/ACBP) characterized as a ligand at central BDZ receptors, at PBR with involvement in the regulation of steroidogenesis, and as an intracellular acyl-CoA transporter, are both known to interact with BDZ in adult systems. We investigated their expression after prenatal exposure to BDZ. Diazepam (1.25 mg/kg per day s.c.) was administered to time-pregnant Long Evans rats from gestational day (GD) 14 to 20. Expression of mRNAs encoding for PBR and for DBI/ACBP was studied in the same animals with (33)P-labeled 60 mer oligonucleotides (oligos) by in situ hybridization at GD20, and with (32)P-labeled oligos by Northern blot in steroidogenic and immune organs at postnatal day (PN) 14 and in adult offspring. Prenatal diazepam increased DBI/ACBP mRNA expression in male fetal adrenal and in fetal and PN14 testis. Thymus exhibited increased DBI/ACBP mRNA in male fetuses and in adult female offspring, and reduced organ weight at PN14 in both sexes. In female spleen, an increase in DBI/ACBP mRNA and a decrease in PBR mRNA was seen at PN14. Apart from the finding in spleen, no drug-induced changes in PBR mRNA were observed. The effects of prenatal diazepam were superimposed on treatment-independent sex differences in DBI/ACBP mRNA and PBR mRNA expression. Our data indicate that expression of DBI/ACBP mRNA in steroidogenic and immune organs can be affected by exposure to BDZ during ontogeny, while PBR mRNA expression appears to be less sensitive. They further reveal marked sex differences in the developmental patterns of the two proteins during pre- and postpubertal ontogeny.

Adrenal Glands↗

A cis-acting element known to block 3' mRNA degradation enhances expression of polyA-minus mRNA in wild-type yeast cells and phenocopies a ski mutant.

mRNA lacking a 3' polyA tail is not translated efficiently in wild-type eukaryotic cells, but is translated efficiently in yeast ski mutants. This enhanced expression could be due to altered translational specificity. However, as the SKI genes are required for 3' mRNA degradation, it could be a consequence of inhibition of 3' mRNA decay. Therefore, we asked if inhibition of 3' decay of a polyA-minus mRNA in cis would allow its efficient expression in wild-type cells. Capped in vitro reporter transcripts were prepared with or without a 3' cis-acting element known to inhibit 3' degradation (oligoG) and electroporated into yeast cells. The addition of oligoG to a polyA-minus mRNA enhanced expression 30-fold in wild-type cells. This level of expression was the same as that for an oligoG-minus, polyA-minus transcript in a ski mutant. The addition of oligoG did not significantly enhance the expression of polyA-minus mRNA in a ski mutant. The oligoG-dependent increase in expression was due to an increase in initial rate of translation and an increase in the functional half-life of the mRNA, similar to the effects observed in a ski mutant. The enhanced expression of the oligoG-containing RNA did not require Pab1p. We conclude that the enhanced translation of polyA-minus RNA in a ski mutant is due to inhibition of 3' mRNA degradation. Furthermore, a polyA-minus mRNA is expressed in wild-type cells when terminated in an element known to inhibit 3' decay in cis.

3' Untranslated Regions↗

Quantitative real-time RT-PCR analysis of NY-ESO-1 and LAGE-1a mRNA expression in normal tissues and tumors, and correlation of the protein expression with the mRNA copy number.

We investigated NY-ESO-1 and LAGE-1a mRNA expression in normal tissues and various types of cancer by quantitative real-time RT-PCR. In addition to their high expression in the testis, we observed a low expression of NY-ESO-1 mRNA in the placenta, pancreas and liver, and no expression in 12 other normal tissues. We also observed a low expression of LAGE-1a mRNA in the placenta and ovary, and marginal expression in 13 other normal tissues. In contrast to the previous finding that NY-ESO-1 and LAGE-1a mRNAs were mostly co-expressed in solid tumors, we found an independent expression of NY-ESO-1 and LAGE-1a mRNAs. NY-ESO-1 mRNA expression was mostly associated with LAGE-1a mRNA expression in esophageal and liver cancers, but not in prostate cancer. Immunohistochemistry (IHC) using NY-ESO-1-specific ES121 mAb showed that NY-ESO-1 protein was detected in 6 of 9 and 3 of 10 NY-ESO-1 mRNA-positive specimens from esophageal and liver cancers, respectively. NY-ESO-1 protein expression was correlated with the copy numbers of NY-ESO-1 mRNA. IHC was also performed using ES121 mAb and B9.8 mAb recognizing both NY-ESO-1 and LAGE-1a in 4 esophageal and 6 liver cancer specimens preferentially expressing LAGE-1a mRNA. B9.8-specific staining was observed weakly and focally in one liver cancer specimen expressing >10(5) copies of LAGE-1a mRNA.

Antibodies, Monoclonal↗

Cytokine mRNA are preferentially increased relative to secretory granule protein mRNA in mouse bone marrow-derived mast cells that have undergone IgE-mediated activation and degranulation.

The levels of mRNA that encode a number of cytokines have been reported by several laboratories to be increased in mouse mast cells after their IgE-bearing receptors have been cross-linked with Ag. In this study, we have compared the mRNA levels for Fc epsilon RI alpha, three cytokines (IL-6, granulocyte-macrophage CSF, and TNF-alpha), actin and three secretory granule-localized proteins (carboxypeptidase A, proteoglycan peptide core, and a generic serine protease) in mouse bone marrow-derived mast cells (BMMC) before and after IgE-mediated activation and degranulation to determine the kinetics and specificity of mRNA induction. An antigen concentration of approximately 10 ng/ml was optimal for the release of histamine from IgE-sensitized BMMC and for the generation and release of a cytokine that was functionally and immunochemically identical to TNF-alpha. In kinetic experiments, the levels of TNF-alpha, IL-6, and granulocyte-macrophage CSF mRNA increased greater than 23-fold 0.5 to 1 h after activation. As assessed by in situ hybridization, virtually all BMMC contained detectable proteoglycan peptide core mRNA before and after exposure to Ag, but only approximately one-half of the Ag-treated cells in the culture contained IL-6 mRNA 1 h after activation. There was a slight transient increase at 4 h in the level of proteoglycan peptide core mRNA, but no increase in the levels of those highly expressed mRNA that encode actin, Fc epsilon RI alpha, carboxypeptidase A, and serine protease. Thus, despite the remarkable increment in the levels of the transcripts that encode cytokines in BMMC after IgE-mediated, Ag-dependent activation, the levels of those transcripts that encode a plasma membrane-localized recognition receptor and several constituents of the secretory granule remain essentially unchanged. The failure to increase substantially the level of protease and proteoglycan peptide core mRNA in mast cells after the activation/secretion response suggests that regranulation of mast cells is a slow process.

Animals↗

Heterogeneity at the 5' end of rat acetyl-coenzyme A carboxylase mRNA. Lipogenic conditions enhance synthesis of a unique mRNA in liver.

Multiple forms of acetyl-CoA carboxylase mRNA were previously detected in the mammary gland (Lopez-Casillas, F., Luo, X., Kong, I.-S., and Kim, K.-H. (1989) Gene, in press). We have now established that the rat liver also contains heterogeneous acetyl-CoA carboxylase mRNA populations that differ in the 5'-untranslated region. In addition, the liver contains a unique form of acetyl-CoA carboxylase mRNA in which the 5'-nontranslated end differs from the species in mammary gland. The 5' end of this unique species was characterized using a procedure for cloning minute amounts of primer extension products (pAU clones). This procedure should also be useful for obtaining full length clones of other mRNAs. The DNA sequence of pAU clones indicates that this liver-specific acetyl-CoA carboxylase mRNA has a 315-base long untranslated region. The first 242 nucleotides replace the 5' end of the predominant acetyl-CoA carboxylase mRNA found in the mammary gland (FL56 type). Under lipogenic conditions the unique liver acetyl-CoA carboxylase mRNA increases and is the major species of acetyl-CoA carboxylase mRNA. Livers from rats fed a normal diet and the mammary glands of lactating rats do not contain detectable amounts of the pAU type mRNA. On the other hand, the epididymal adipose tissue from these animals contains mainly the pAU type and only minimal amounts of the FL56 type. The multiple forms of acetyl-CoA carboxylase mRNA appear to be generated by differential splicing. In addition, transcription appears to be physiologically regulated by the use of tissue-specific acetyl-CoA carboxylase gene promoters.

Acetyl-CoA Carboxylase↗