Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0017638 (glioma)
 30,880 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The 5'-flanking region of the calcineurin A alpha gene was isolated from a rat genomic library. It lacked TATA and CAAT boxes but contained G+C-rich regions, and was demonstrated to function as a strong promoter in neuronal cell lines (NG108-15 mouse neuroblastoma x rat glioma hybrid cells or N1E115 mouse neuroblastoma cells), but not in nonneuronal cell lines (C6 rat glioma or L-M mouse fibroblastoid cells) in a transient chloramphenicol acetyltransferase expression assay. Deletion analysis of the 5'-flanking region revealed that the core promoter region, as well as the sequence critical for cell-type-specific-promoter function, reside within the fragment -107 to +157 with respect to the major transcription initiation site.
 ...
PMID:Molecular cloning and characterization of the promoter region of the calcineurin A alpha gene. 133 33

The 5'-flanking region of the human brain-derived neurotrophic factor (BDNF) gene was isolated from a human placental genomic library using the cDNA fragment for the 5'-noncoding region of human BDNF as a probe. A 3.2 Kbp genomic fragment containing the 5'-flanking region, the first exon and a portion of the first intron was isolated and sequenced. The transcriptional initiation site, identified by S1 nuclease mapping, was located 26 bp downstream from the TATA-like sequence. Several expression plasmids, in which the BDNF promoter regions were fused to the chloramphenicol acetyltransferase (CAT) gene, were constructed. Transient expression in human glioma Hs683 cells demonstrated that a fragment of about 0.5 Kbp from the transcriptional initiation site was sufficient for promoter activity.
 ...
PMID:Characterization of the 5'-flanking region of the human brain-derived neurotrophic factor gene. 133 67

Basal expression of a chimeric gene (pMHO4CAT) consisting of approximately 7 kilobase pairs (kbp) of the 5'-flanking region of the mouse heme oxygenase-1 (HO-1) gene fused to the bacterial chloramphenicol acetyltransferase gene is 2- to 10-fold greater than that of an analogous construct containing only 1287 bp of the 5'-flanking region (pMHO1CAT) in transiently transfected cultured cells. The enhancer activity has been localized to a 268-base pair (bp) fragment positioned approximately 4 kilobase pairs upstream of the transcription initiation site. This fragment contains two high affinity protein binding sites, regions A and B, as determined by DNase I protection assays using nuclear protein extracts from rat C6 glioma cells. Both sites include core sequence elements, TGAGTCA (region A) and TGTGTCA (region B), that resemble the consensus binding site, TGA(G/C)TCA, of the Jun/Fos (AP-1) family of transcription factors. Purified, bacterially expressed AP-1 (c-Jun homodimer) specifically binds to both elements, exhibiting greater affinity for the region A motif. The expression of pMHO4CAT, but not of pMHO1CAT, is stimulated by the phorbol ester 12-O-tetradecanoylphorbol-13-acetate (TPA), and the 268-bp enhancer fragment confers TPA inducibility and c-Jun/c-Fos transactivation to the heterologous SV40 promoter. These functions are mediated by the AP-1 binding sites as multiple copies of the region A motif also confer TPA induction and c-Jun/c-Fos transactivation upon a heterologous promoter.
 ...
PMID:Distal AP-1 binding sites mediate basal level enhancement and TPA induction of the mouse heme oxygenase-1 gene. 140 Apr 99

Glucocorticoids enhance proenkephalin gene expression in several cell types. To elucidate the mechanism(s) involved, we analyzed the potentiation by dexamethasone of the cAMP-dependent increase in proenkephalin mRNA levels elicited by forskolin in C6 rat glioma cells. This potentiation did not require ongoing protein synthesis. In nuclear run-on transcription assays, dexamethasone alone did not alter proenkephalin transcription, but strongly increased the magnitude and duration of transcriptional elevation by forskolin through a direct action not requiring ongoing protein synthesis. Dexamethasone did not alter basal or stimulated cAMP levels. To search for functionally cooperative glucocorticoid and cAMP regulatory elements, we transfected C6 cells with plasmids containing the chloramphenicol acetyltransferase (CAT) gene under the control of rat proenkephalin sequences from bases -5800 to +703. Maximum stimulation of transiently expressed CAT activity by forskolin required more than 145 and 190 or fewer base pairs of 5'-flanking sequence, implicating sequences up-stream from the previously described cAMP-inducible enhancer. Dexamethasone reduced forskolin-stimulated CAT expression from plasmids with 190 or more base-pairs of 5'-flanking sequence, an effect apparently involving multiple up-stream regions. Dexamethasone also reduced forskolin-stimulated CAT mRNA levels in C6 cells stably transfected with proenkephalin/CAT chimeric genes in the presence or absence of proteins synthesis. In summary, we demonstrate that glucocorticoids and cAMP synergize positively in regulating transcription of the endogenous gene, but interact negatively in regulating the chimeric constructs, which may lack the context or distal element(s) required for positive synergism.
 ...
PMID:Proenkephalin gene expression in C6 rat glioma cells: potentiation of cyclic adenosine 3',5'-monophosphate-dependent transcription by glucocorticoids. 165 36

A genomic clone for rat tyrosine hydroxylase (TH) was isolated and a fragment containing 503 bp upstream of the transcription start site was sequenced. The BamHI/AluI fragment was inserted into a plasmid carrying the coding sequence for bacterial chloramphenicol acetyltransferase (CAT). Another construct with the 5' sequence truncated to -151 bp also was prepared. When these were introduced into several mammalian cell lines, including C6 glioma, BE(2) neuroblastoma, CV-1 or Ltk- fibroblasts, different basal levels of CAT expression were observed. In the fibroblast lines, THCAT constructs were not expressed unless the cells were treated with forskolin or TPA. However, the low basal expression was not correlated to endogenous expression as THCAT constructs expressed comparably in BE(2)C, HeLa, and C6 glioma. Treatment of any of the cell lines with forskolin, TPA, or a combination of the two agents stimulated the expression by at least two-fold in all cell lines and the maximally induced levels were at least 10-fold over promoterless controls. These data indicate that the essential promoter elements as well as those conferring responsivity to cyclic AMP reside within 151 bp of the transcription start site. However, the array of elements regulating cell-type expression lie, at least in part, beyond the 500-bp region examined. Further, a role for phosphorylation in the regulation of basal and induced transcription of TH is suggested.
 ...
PMID:Effects of second messenger system activation on functional expression of tyrosine hydroxylase fusion gene constructs in neuronal and nonneuronal cells. 168 57

We have isolated the human angiotensinogen gene from a genomic library and determined the exon-intron junction sequences. The gene is 12 kilobases long and consists of five exons interrupted by four introns, as a single copy in the human genome. Of particular interest are the positions of the introns in the human angiotensinogen gene which are identical to those in the highly homologous human alpha 1-antitrypsin and alpha 1-antichymotrypsin genes, as well as rat and mouse angiotensinogen genes. Northern blot analysis showed that human hepatoma cells (HepG2) produce a large amount of angiotensinogen mRNA but not human glioma cells (T98G). To assay the promoter activity, the 1.3-kilobase genomic fragment containing the 5'-flanking region, first exon, and a part of first intron at positions -1222 to +44 was fused upstream to the chloramphenicol acetyltransferase gene, then transfected into HepG2 and T98G cells. The gene sequence was active only in HepG2 cells, suggesting the presence of a functional promoter. Analysis of deletion mutants demonstrated that the 76-base pairs region from -32 to +44 containing the TATA box and first exon is the minimal promoter, whose activity is as high as that of the SV40 enhancer-promoter. Since the basal expression of the human angiotensinogen gene is much higher in HepG2 than T98G cells, these results may reflect cell-specific differences in the gene transcription.
 ...
PMID:Structure and expression of the human angiotensinogen gene. Identification of a unique and highly active promoter. 169 23

Mouse lactoferrin is expressed in a variety of tissues under different types of control. To understand how molecular mechanisms govern the mode of lactoferrin expression, we isolated and characterized the 5'-flanking region of the lactoferrin gene. Several clones containing lactoferrin gene fragments were isolated from a mouse (129/J) genomic library including clone lambda J14, which contains a 7.5-kilobase pair 5'-flanking sequence. Sequence analysis of the region flanking the transcription initiation site revealed the following: a TATA-like sequence, two CAAT boxes, three GC boxes including one within the first intron, an AP2 site, seven PU boxes, an AC-rich region, a B1 sequence, and an estrogen-responsive element consensus sequence over-lapping with a chicken ovalbumin upstream promoter-binding element. Footprinting analysis demonstrated that several regions, including the putative estrogen-responsive element region, in the 5'-flanking sequence were protected from DNase I digestion. Promoter fragments were cloned into a chloramphenicol acetyltransferase receptor plasmid to study functional activity. The mouse lactoferrin gene promoter was active in human endometrium carcinoma RL 95-2 cells and in rat glioma C6 cells. Multiple upstream elements modulated the basal transcriptional promoter activity. The transcription level directed by this minimal promoter was controlled by both positive (between -1739 and -922) and negative (between -2644 and -1739, and between -589 and -291) regulatory sequences. A tissue-specific regulatory sequence was critical for the establishment of lactoferrin expression in human endometrium carcinoma cells, but not in rat glioma cells located between -1739 and -922. Reporter plasmid 0.6 mL14-CAT, containing the estrogen-responsive element sequence, was estrogen-responsive in the presence of estrogen receptor in human endometrium carcinoma RL 95-2 cells.
 ...
PMID:Characterization of estrogen-responsive mouse lactoferrin promoter. 193 12

The expression of class II major histocompatibility (MHC) antigens is central to the mounting of a successful immune response. Understanding the molecular mechanisms involved in the induction of class II MHC expression may therefore provide the knowledge necessary to manipulate the immune system appropriately. We are particularly interested in the induction of class II MHC antigens on cells in the brain, because of the potential involvement of such brain cells in the initiation and perpetuation of autoimmune-like diseases of the central nervous system. We examined the mechanisms involved in interferon-gamma (IFN-gamma) induction of class II MHC antigens on a human glioblastoma multiforme cell line. This paper describes the identification of a 297-bp (base pair) fragment of the class II MHC DR alpha chain gene which is involved in IFN-gamma induction. We were able to identify this IFN-gamma responsive sequence by preparing recombinant plasmids containing 5' flanking pieces of the human DR alpha chain gene placed upstream of the indicator gene, chloramphenicol acetyltransferase (CAT). These recombinant plasmids were transfected into human glioma cells which were then cultured in the presence or absence of IFN-gamma. After 48 hr, transient expression of CAT was assayed by thin layer chromatography. CAT enzyme activity was significantly increased only in IFN-gamma-treated cells. This increase was also reflected at the RNA level in that IFN-gamma treatment resulted in higher CAT transcripts. A computer homology search revealed a possible consensus sequence shared among different IFN-gamma-inducible genes.
 ...
PMID:Identification of an interferon-gamma response region 5' of the human histocompatibility leukocyte antigen DR alpha chain gene which is active in human glioblastoma multiforme lines. 302 77

Expression of the human galanin gene was analysed using a 3.5-kb DNA fragment comprising the 5'-flanking sequence of the gene. This sequence contains a TATA box (ATATATA) preceded by numerous potential binding sites for transcription factors such as SP1, AP2, and NF kappa B. Three half-palindromic estrogen response elements (EREs, GGTCA) are also found at positions -1,162, -361, and -122 bp relative to the transcription start site. To localize functionally important portions of the promoter region, several shorter fragments of the galanin 5'-flanking region were placed upstream from the chloramphenicol acetyltransferase (CAT) reporter gene. In transient transfection assays, all constructs demonstrated substantial transcriptional activity in both rat glioma/mouse neuroblastoma hybrid cells (NG108-15) and Chinese hamster ovary (CHO-K1) cells. Comparison of the basal expression levels of the different constructs suggests the presence of a negative modulator between positions -1,891 and -207. When cotransfected into NG108-15 cells with the human estrogen receptor cDNA, estrogen did not induce transcription of the human galanin gene at physiological levels of estrogen receptor, although transcription was induced up to 30-fold in the presence of high levels of receptor.
 ...
PMID:Characterization of the 5'-flanking region of the human preprogalanin gene. 753 7

Regulation of lactate dehydrogenase (LDH) (EC 1.1.1.27) isozymes occurs through a multitude of physiological signals. Here, we show that modulation of LDH A subunit occurs via the protein kinase C pathway. Activators of protein kinase C, such as tetradecanoylphorbol acetate (TPA) and dioctanoylglycerol (DG), caused a 3-4-fold accumulation of LDH A subunit mRNA in rat C6 glioma cells. The specific protein kinase C inhibitor bisindolylmaleimide GF 109203X prevented the TPA-induced increase of LDH A subunit mRNA. To analyze the molecular basis of these effects in more detail, the transcription-modulatory effects of TPA and DG were evaluated in transient transfection assays using plasmids which contain LDH A subunit promoter fragments fused to a chloramphenicol acetyltransferase reporter gene. Both effector agents caused a marked increase of the transcriptional activity of an LDH -830/+25 bp promoter/CAT construct. In contrast, a phorbol ester which fails to activate protein kinase C, phorbol 12 beta,13 alpha-didecanoate, had no effect on the LDH promoter activity. Transient transfection analysis of LDH promoter deletion/CAT constructs, DNA/protein binding assays, including footprint and gel shift analyses, identified a TRE/AP-1 enhancer module at position -294 bp which was the target for the protein kinase C-mediated signal transduction pathway. Thus, our data demonstrate an active role of the protein kinase C signal pathway in regulating LDH A subunit gene expression which may be significant in regulating LDH isozyme patterns under various physiologic conditions.
 ...
PMID:Transcriptional regulation of the lactate dehydrogenase A subunit gene by the phorbol ester 12-O-tetradecanoylphorbol-13-acetate. 775 43


1 2 3 Next >>