Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0027819 (neuroblastoma)
 27,800 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We show that expression of the p34cdc2 and cyclin A genes is induced by interleukin-2 in normal human T cells and present evidence to support the idea that these genes are deregulated in leukemic T cells. Our DNA sequencing data indicate that the promoter region of the p34cdc2 gene contains putative E2F-like binding sites which are recognized by Rb and binding sites for c-myb, Sp1, and ATF, and that the promoter region of the cyclin A gene contains binding sites for p53, Sp1, and ATF. In this study we focus on the effect of p53 and Rb on these cell cycle-regulatory genes. Cotransfection of Y79 human retinoblastoma cells with a p34cdc2 promoter-luciferase expression vector and a plasmid expressing the retinoblastoma gene (RB) indicated that RB suppresses p34cdc2 expression. Cotransfection of B104 rat neuroblastoma cells with a cyclin A promoter-luciferase expression vector and a plasmid expressing the normal or mutant p53 indicated that only the normal p53 suppresses cyclin A expression. In normal T cells, PHA stimulation reduces the amount of complexes in the p34cdc2 promoter between the E2F-like binding site and the RB gene product. These complexes were not detected in leukemic T cells. Our data support the idea that tumor suppressors modulate the expression of cell cycle-regulatory genes: RB regulates p34cdc2 expression and p53 regulates cyclin A expression.
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PMID:Effect of tumor suppressors on cell cycle-regulatory genes: RB suppresses p34cdc2 expression and normal p53 suppresses cyclin A expression. 827 2

Choline acetyltransferase (ChAT) is specifically expressed in cholinergic neurons. To identify control mechanisms regulating the cell-specific expression of the gene encoding ChAT, transient expression of the luciferase gene driven by human ChAT gene 5'flanking sequences was compared in cholinergic and noncholinergic cell lines. Analysis of the gene indicated the presence of two regulatory elements with selective silencing activity. These elements, located between nucleotides -2043 to -3347 and nucleotides -3347 to -6550, act cooperatively to repress promoter activity > 10-fold in a human adrenergic neuroblastoma cell line, SHSY5Y, and a human osteosarcoma cell line, 143 TK-, while exhibiting less than a two-fold effect in cholinergic cell lines. Deletion of either nucleotides -2043 to -3347 or nucleotides -3348 to -6550 reduced cell-specific repression by approximately half. Such differential repression appears to be responsible for the selective expression of the ChAT component of the cholinergic phenotype.
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PMID:Cholinergic neuron-specific expression of the human choline acetyltransferase gene is controlled by silencer elements. 833 50

The 5'-flanking region of the human ADP-ribosylation factor 3 gene contains the features of a housekeeping gene. It lacks a TATA or CAAT box, has several GC boxes within a highly GC-rich region, and utilizes multiple transcription initiation sites. The cis-acting elements involved in regulating expression of the gene were identified by transient transfections of IMR-32 neuroblastoma cells. Reporter plasmids were modified to facilitate construction of defined promoter deletions linked to chloramphenicol acetyltransferase or luciferase using ligation-independent cloning. Transfection analyses indicated that sequences within 58 base pairs of the transcription initiation site were necessary for full expression, in particular a sequence containing the 10-base pair palindrome TCTCGCGAGA. Electrophoretic mobility shift assays performed with IMR-32 nuclear extracts demonstrated that a DNA-binding protein, termed TLTF, bound to an oligonucleotide containing this palindrome. Competition experiments showed that mutations within the core of the palindrome abolished in vitro binding and that the same protein bound to a 5'-proximal sequence. Expression of the promoter containing a mutated palindrome was reduced dramatically, consistent with the conclusion that this region functions in vivo to control expression of the ARF3 gene.
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PMID:Characterization of the human ADP-ribosylation factor 3 promoter. Transcriptional regulation of a TATA-less promoter. 847 23

Cholinergic muscarinic receptor genes are members of the G-protein receptor gene superfamily. In this study we describe the structure of the gene and promoter of the rat m4 muscarinic receptor gene. A rat cosmid clone containing the coding region for the m4 gene and 25 kilobases of upstream sequence was isolated. This clone directed expression of the rat m4 gene when introduced in IMR32 cells, a human neuroblastoma that expresses m4, but did not drive expression when introduced into Chinese hamster ovary cells, a line that does not express the m4 gene. S1 nuclease, modified 5'-rapid amplification of cDNA ends and polymerase chain reaction analysis of rat cosmid DNA and cDNA showed that the gene consists of a 2.6-kilobase coding exon, extending 34 base pairs (bp) upstream from the initiating ATG, separated from a 460-493 bp noncoding exon by a 4.8-kilobase intron. DNA sequence analysis shows that the non-coding exon is GC-rich and that the promoter does not contain a TATA or CAAT box and has several consensus sequences for enhancer elements including five Sp-1 binding sites, one AP-2 site, one AP-3 binding site and two E-boxes within the proximal 600 bp. A reporter construct consisting of 1440 bp of flanking DNA and 80 bp of the first exon cloned into a luciferase reporter plasmid, drove cell specific expression in transient transfection assays. Removal of 1088 bp of the 5' end of this construct resulted in expression in non-m4 expressing cell lines suggesting there is a repressor element in this region.
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PMID:Structure of the m4 cholinergic muscarinic receptor gene and its promoter. 853 49

To investigate the ability of the retinoblastoma gene product (RB protein, pRB) to regulate its own expression, cotransfection assays using human RB promoter-luciferase fusion plasmids and a human pRB expression plasmid were employed. In B104, a rat neuroblastoma cell line, pRB stimulated luciferase activity about 2-fold from the wild-type promoter, and about 4-fold from a mutant promoter with a mutation in the retinoblastoma binding factor 1 (RBF-1) site. The RB-responsive region was mapped to a novel 44 bp sequence in the 5' untranslated region in both wild-type and mutant promoters. When apparent stimulation of luciferase activity by pRB was observed, the luciferase mRNA level did not increase, suggesting that through this 44 bp region, pRB could post-transcriptionally regulate its own expression.
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PMID:Identification of an RB-responsive region in the 5' untranslated region of the RB gene. 862 Apr 63

1. NIE-115 mouse neuroblastoma cells were studied under voltage clamp in the whole-cell patch-clamp configuration. Peak currents induced by bath application of 5-hydroxytryptamine (5-HT) were inwardly rectifying, reversed at 0.4 +/- 0.2 mV (mean +/- s.e.mean), and were approximately half-inhibited (at 1 microM 5-HT) by 2 nM of the 5-HT3 selective antagonist MDL-72222 (3-tropanyl-3,5-dichlorobenzoate). 2. Peak inward currents activated by a low concentration of 5-HT at a holding potential of -50 mV were potentiated by volatile general anaesthetics. At their human minimum alveolar concentrations (MACs), the degree of potentiation increased in the order isoflurane < halothane < enflurane < methoxyflurane. Potentiation by methoxyflurane was independent of membrane potential in the range -70 mV to +40 mV. The reversal potential was the same in the presence and absence of methoxyflurane. 3. Methoxyflurane shifted the 5-HT dose-response curve to lower 5-HT concentrations, without significantly changing the Hill coefficient or maximum response. The EC50 concentration for 5-HT decreased from 1.86 +/- 0.02 microM to 1.07 +/- 0.11 microM (means +/- s.e.mean) due to the presence of 1 MAC (270 microM) methoxyflurane. 4. In contrast to the volatile anaesthetics, the barbiturate anaesthetic, thiopentone, inhibited the 5-HT3 receptor. Hill analysis of thiopentone dose-response data gave an average IC50 = 117 +/- 8 microM thiopentone and Hill coefficient = 1.6 +/- 0.2 (means +/- s.e.mean). These parameters were not significantly different for data obtained at 5-HT concentrations above and below the control EC50 concentration for 5-HT, consistent with non-competitive inhibition. 5. The n-alcohols occupied an intermediate position between the volatile and barbiturate anaesthetics. The lower alcohols (butanol and hexanol) potentiated 5-HT responses at low alcohol concentrations but inhibited them at high concentrations. In contrast, the higher alcohols (octanol, decanol, dodecanol, tridecanol, tetradecanol and pentadecanol) produced no potentiation, but only inhibition, at all alcohol concentrations. 6. Inhibition of the 5-HT3 receptor by the n-alcohols exhibited a cutoff in potency similar to those previously found for tadpoles, luciferase enzymes and a neuronal nicotinic acetylcholine receptor channel.
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PMID:Actions of general anaesthetics on 5-HT3 receptors in N1E-115 neuroblastoma cells. 873 Jul 47

Secretogranin II (SgII) is a member of the granin family of secretory proteins, which are selectively expressed in neuroendocrine cells. As a first step in understanding the molecular basis for cell type-specific expression of SgII, we isolated a 12-kb clone from a rat genomic library that contained the entire rat SgII coding region, the transcription initiation site, and approximately 3 kb of 5'-flanking region. Within 75 bp of the transcription start site (+1) we located a TATA box and a consensus cAMP responsive element. Within the 5'-flanking region, a number of potential cis-acting elements were identified, including 2 Pit-1 binding sites, 15 E box motifs, and near-perfect matches for AP-1 and AP-2 sites. To demonstrate cell type-specific expression the rat SgII gene, a plasmid containing 2.6 kb of the 5'-flanking region of the SgII gene fused to the luciferase reporter gene (p2774Luc) was transfected into rat pheochromocytoma PC-12 cells, rat pituitary GH4C1 (GH) cells, human BE(2)-M17 (M17) neuroblastoma cells, and mouse fibroblast NIH/3T3 cells. The promoter activity was 6- to 36-fold higher in neuroendocrine cells than in NIH/ 3T3 cells. Progressive deletions in the 5'-flanking region to 61 bp upstream of the start site (p223Luc) had no effect on promoter activity in PC-12 cells. On the other hand, a 5'-deletion in the SgII promoter to -1032 increased promoter activity 3.8-fold in GH cells. This level of expression was maintained when the SgII promoter was further truncated to -189, whereas truncation to -61 resulted in a 2.6-fold reduction in promoter activity. These results suggest that the sequence between -61 and +162 bp is sufficient for SgII promoter activity in PC-12 cells. However, other elements in the 5'-flanking region contribute to both positive and negative regulation of the rat SgII gene in GH cells.
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PMID:Cell-specific expression of the rat secretogranin II promoter. 875 52

We have isolated and characterized the 5'-flanking region and the proximal polyadenylation site of the human 5-HT transporter gene. The major gene transcript is 2,793 bp in length and it contains 208 bp of 5'-untranslated region (5'-UTR) and 694 bases of 3'-UTR. While only a single mRNA species occurs in rats and mice, the most proximal signal for polyadenylation in the human gene appears to be highly degenerate in comparison to the rat and murine motif. This polyadenylation signal-like motif may lead to alternate usage of additional polyadenylation sites resulting in multiple mRNA species in humans. A TATA-like motif and several potential binding sites for transcription factors including AP1, AP2, SP1, and a cAMP response element (CRE)-like motif are present in the 5'-flanking region. A approximately 1.7 kb fragment beginning 217 bp downstream from the transcription start site, which had been ligated into a luciferase reporter vector and transiently expressed in JAR human placental choriocarcinoma cells, displayed both constitutive and forskolin/cholera toxin-induced promoter activity. Functional promoter mapping revealed that there are negative attenuating elements between bp -1,428 and -1,185 and positive elements between bp -1,184 and -78 from the transcription initiation site. Studies with deletional mutants also indicated that core promoter sequences are contained within 78 bp of the transcription start site and that regulation of cAMP-inducible promoter activity depends on multiple cis-acting elements including two AP1 binding sites and a single CRE-like element located at bp -99. Our findings suggest that (1) the 5-HT transporter gene promoter is active in human JAR cells, but inactive in 5-HT transporter-deficient human SK-N-SH neuroblastoma and HeLa cells, (2) the information contained within 1.4 kb of 5'-flanking sequence is sufficient to confer its cell-specific expression, (3) the promoter responds to cAMP induction, and (4) the expression of the 5-HT transporter gene is regulated by a combination of positive and negative cis-acting elements operating through a basal promoter unit defined by a TATA-like motif.
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PMID:Functional promoter and polyadenylation site mapping of the human serotonin (5-HT) transporter gene. 878 73

Glial cell line-derived neurotrophic factor (GDNF), a member of the transforming growth factor-beta family of growth factors, was first identified by its ability to promote the survival of midbrain dopaminergic neurons in culture. We demonstrate that GDNF treatment of several neuroblastoma cell lines leads to dose-dependent tyrosine phosphorylation of the RET receptor and that other transforming growth factor-beta family members are not able to activate the RET receptor. GDNF treatment of neuroblastoma cells also results in increased transcription of an Elk luciferase reporter gene, suggesting that GDNF activates the mitogen-activated protein kinase signal transduction pathway.
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PMID:Glial cell line-derived neurotrophic factor signals through the RET receptor and activates mitogen-activated protein kinase. 879 76

A 5.4 kilobase-pair segment of DNA flanking the 5' end of Hel-N1 was isolated and characterized. Primer extension studies with normal human brain and neuroblastoma cells revealed a major and minor transcription-initiation site. Sequence analysis of the initial 536 bp upstream to the major start site revealed a core promoter (-1 to -181) which contained two CCAAT boxes, a weakly-conserved TATA box, and an SP1 site. This region was also moderately GC-rich (62%). Using a transient luciferase-reporter-gene assay, the core promoter was found to be essential for basal transcription both in neural (PC12) and non-neural (HeLa and glial) cell types. Two positive regulatory elements, however, were identified in the initial 536 bp (-1 to -181 and -182 to -350) which produced a five- to six-fold increase in transcriptional activity in PC12 cells vs. HeLa or glial cells. These elements, therefore, were sufficient to confer cell-specific enhanced transcription and likely contribute to the neuronal specificity of Hel-N1 mRNA expression.
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PMID:Cloning the 5' flanking region of neuron-specific Hel-N1: evidence for positive regulatory elements governing cell-specific transcription. 881 91


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