scholarly journals Requirement of glucose metabolism for regulation of glucose transporter type 2 (GLUT2) gene expression in liver

1996 ◽  
Vol 314 (3) ◽  
pp. 903-909 ◽  
Author(s):  
Franck RENCUREL ◽  
Gérard WAEBER ◽  
Bénédicte ANTOINE ◽  
Francis ROCCHICCIOLI ◽  
Paulette MAULARD ◽  
...  
Keyword(s):  
Gene Expression ◽  
Glucose Metabolism ◽  
Reporter Gene ◽  
Glucose Transporter ◽  
Regulatory Region ◽  
Proximal Fragment ◽  
Mrna Accumulation ◽  
Glut2 Gene

Previous studies have shown that glucose increases the glucose transporter (GLUT2) mRNA expression in the liver in vivo and in vitro. Here we report an analysis of the effects of glucose metabolism on GLUT2 gene expression. GLUT2 mRNA accumulation by glucose was not due to stabilization of its transcript but rather was a direct effect on gene transcription. A proximal fragment of the 5´ regulatory region of the mouse GLUT2 gene linked to a reporter gene was transiently transfected into liver GLUT2-expressing cells. Glucose stimulated reporter gene expression in these cells, suggesting that glucose-responsive elements were included within the proximal region of the promoter. A dose-dependent effect of glucose on GLUT2 expression was observed over 10 mM glucose irrespective of the hexokinase isozyme (glucokinase Km 16 mM; hexokinase I Km 0.01 mM) present in the cell type used. This suggests that the correlation between extracellular glucose and GLUT2 mRNA concentrations is simply a reflection of an activation of glucose metabolism. The mediators and the mechanism responsible for this response remain to be determined. In conclusion, glucose metabolism is required for the proper induction of the GLUT2 gene in the liver and this effect is transcriptionally regulated.

scholarly journals cAMP prevents the glucose-mediated stimulation of GLUT2 gene transcription in hepatocytes

1997 ◽  
Vol 322 (2) ◽  
pp. 441-448 ◽  
Author(s):  
Franck RENCUREL ◽  
Gérard WAEBER ◽  
Christophe BONNY ◽  
Bénédicte ANTOINE ◽  
Paulette MAULARD ◽  
...  
Keyword(s):  
Gene Expression ◽  
Reporter Gene ◽  
Gene Transcription ◽  
Glucose Transporter ◽  
Hepatoma Cell ◽  
Inhibitory Effect ◽  
Hepatoma Cell Line ◽  
Mrna Accumulation ◽  
Glut2 Gene

Glucose homoeostasis necessitates the presence in the liver of the high Km glucose transporter GLUT2. In hepatocytes, we and others have demonstrated that glucose stimulates GLUT2 gene expression in vivo and in vitro. This effect is transcriptionally regulated and requires glucose metabolism within the hepatocytes. In this report, we further characterized the cis-elements of the murine GLUT2 promoter, which confers glucose responsiveness on a reporter gene coding the chloramphenicol acetyl transferase (CAT) gene. 5´-Deletions of the murine GLUT2 promoter linked to the CAT reporter gene were transfected into a GLUT2 expressing hepatoma cell line (mhAT3F) and into primary cultured rat hepatocytes, and subsequently incubated at low and high glucose concentrations. Glucose stimulates gene transcription in a manner similar to that observed for the endogenous GLUT2 mRNA in both cell types; the -1308 to -212 bp region of the promoter contains the glucose-responsive elements. Furthermore, the -1308 to -338 bp region of the promoter contains repressor elements when tested in an heterologous thymidine kinase promoter. The glucose-induced GLUT2 mRNA accumulation was decreased by dibutyryl-cAMP both in mhAT3F cells and in primary hepatocytes. A putative cAMP-responsive element (CRE) is localized at the -1074/-1068 bp region of the promoter. The inhibitory effect of cAMP on GLUT2 gene expression was observed in hepatocytes transfected with constructs containing this CRE (-1308/+49 bp fragment), as well as with constructs not containing the consensus CRE (-312/+49 bp fragment). This suggests that the inhibitory effect of cAMP is not mediated by the putative binding site located in the repressor fragment of the GLUT2 promoter. Taken together, these data demonstrate that the elements conferring glucose and cAMP responsiveness on the GLUT2 gene are located within the -312/+49 region of the promoter.

scholarly journals Evidence for a transient inhibitory effect of insulin on GLUT2 expression in the liver: studies in vivo and in vitro

1993 ◽  
Vol 293 (1) ◽  
pp. 119-124 ◽  
Author(s):  
C Postic ◽  
R Burcelin ◽  
F Rencurel ◽  
J P Pegorier ◽  
M Loizeau ◽  
...  
Keyword(s):  
Gene Expression ◽  
Glucose Transporter ◽  
Primary Cultures ◽  
Rat Hepatocytes ◽  
Inhibitory Effect ◽  
Mrna Concentration ◽  
Glut2 Gene ◽  
Effect Of Glucose

The glucose transporter GLUT2 is expressed predominantly in the liver. Previous studies have shown that glucose increases GLUT2 mRNA concentration in primary cultures of rat hepatocytes. Since insulin controls the glucose metabolism in the liver, it could be involved in the regulation of GLUT2 gene expression. In vivo, hyperinsulinaemia induced a transient inhibitory effect on liver GLUT2 gene expression, the maximal inhibition of GLUT2 mRNA concentration (93 +/- 6%) being observed after 6 h. When hyperglycaemia was associated with hyperinsulinaemia, the decrease in liver GLUT2 mRNA concentration was partially prevented. The respective effects of glucose and insulin were studied in vitro by primary culture of rat hepatocytes. Insulin alone exerted a transient inhibitory effect on GLUT2 mRNA concentration. When insulin and glucose (10-20 mM) were associated, the stimulatory effect of glucose on GLUT2 gene expression was predominant. In conclusion, the present study shows that GLUT2 mRNA concentration was conversely regulated by insulin and glucose, both in vitro and in vivo.

scholarly journals Synergistic activation of ADH2 expression is sensitive to upstream activation sequence 2 (UAS2) orientation, copy number and UAS1-UAS2 helical phasing.

1995 ◽  
Vol 15 (6) ◽  
pp. 3442-3449 ◽  
Author(s):  
M S Donoviel ◽  
N Kacherovsky ◽  
E T Young
Keyword(s):  
Gene Expression ◽  
Binding Site ◽  
Reporter Gene ◽  
Copy Number ◽  
Glucose Repression ◽  
Regulatory Protein ◽  
Regulatory Region ◽  
Upstream Regulatory Region ◽  
Specific Sequence

The alcohol dehydrogenase 2 (ADH2) gene of Saccharomyces cerevisiae is under stringent glucose repression. Two cis-acting upstream activation sequences (UAS) that function synergistically in the derepression of ADH2 gene expression have been identified. UAS1 is the binding site for the transcriptional regulator Adr1p. UAS2 has been shown to be important for ADH2 expression and confers glucose-regulated, ADR1-independent activity to a heterologous reporter gene. An analysis of point mutations within UAS2, in the context of the entire ADH2 upstream regulatory region, showed that the specific sequence of UAS2 is important for efficient derepression of ADH2, as would be expected if UAS2 were the binding site for a transcriptional regulatory protein. In the context of the ADH2 upstream regulatory region, including UAS1, working in concert with the ADH2 basal promoter elements, UAS2-dependent gene activation was dependent on orientation, copy number, and helix phase. Multimerization of UAS2, or its presence in reversed orientation, resulted in a decrease in ADH2 expression. In contrast, UAS2-dependent expression of a reporter gene containing the ADH2 basal promoter and coding sequence was enhanced by multimerization of UAS2 and was independent of UAS2 orientation. The reduced expression caused by multimerization of UAS2 in the native promoter was observed only in the presence of ADR1. Inhibition of UAS2-dependent gene expression by Adr1p was also observed with a UAS2-dependent ADH2 reporter gene. This inhibition increased with ADR1 copy number and required the DNA-binding activity of Adr1p. Specific but low-affinity binding of Adr1p to UAS2 in vitro was demonstrated, suggesting that the inhibition of UAS2-dependent gene expression observed in vivo could be a direct effect due to Adr1p binding to UAS2.

Hematopoietic regulatory domain of gata1 gene is positively regulated by GATA1 protein in zebrafish embryos

Development ◽  
2001 ◽  
Vol 128 (12) ◽  
pp. 2341-2350
Author(s):  
Makoto Kobayashi ◽  
Keizo Nishikawa ◽  
Masayuki Yamamoto
Keyword(s):  
Gene Expression ◽  
Reporter Gene ◽  
Regulatory Region ◽  
Ectopic Expression ◽  
Transgenic Fish ◽  
Functional Domain ◽  
Cis Acting ◽  
Gfp Reporter ◽  
Gata Motif

Expression of gata1 is regulated through multiple cis-acting GATA motifs. To elucidate regulatory mechanisms of the gata1 gene, we have used zebrafish. To this end, we isolated and analyzed zebrafish gata1 genomic DNA, which resulted in the discovery of a novel intron that was unknown in previous analyses. This intron corresponds to the first intron of other vertebrate Gata1 genes. GFP reporter analyses revealed that this intron and a distal double GATA motif in the regulatory region are important for the regulation of zebrafish gata1 gene expression. To examine whether GATA1 regulates its own gene expression, we microinjected into embryos a GFP reporter gene linked successively to the gata1 gene regulatory region and to GATA1 mRNA. Surprisingly, ectopic expression of the reporter gene was induced at the site of GATA1 overexpression and was dependent on the distal double GATA motif. Functional domain analyses using transgenic fish lines that harbor the gata1-GFP reporter construct revealed that both the N- and C-terminal zinc-finger domains of GATA1, hence intact GATA1 function, are required for the ectopic GFP expression. These results provide the first in vivo evidence that gata1 gene expression undergoes positive autoregulation.

scholarly journals Differential Gene Expression from Two Transcriptional Units in the cag Pathogenicity Island ofHelicobacter pylori

2001 ◽  
Vol 69 (7) ◽  
pp. 4202-4209 ◽  
Author(s):  
Elizabeth A. Joyce ◽  
Joanne V. Gilbert ◽  
Kathryn A. Eaton ◽  
Andrew Plaut ◽  
Andrew Wright
Keyword(s):  
Gene Expression ◽  
Cell Monolayer ◽  
Regulatory Region ◽  
Immunological Response ◽  
Pathogenicity Island ◽  
Gastric Disease ◽  
Regulatory Sequences ◽  
H Pylori

ABSTRACT Infection with Helicobacter pylori strains containing the cag Pathogenicity Island (cag PAI) is strongly correlated with the development of severe gastric disease, including gastric and duodenal ulceration, mucosa-associated lymphoid tissue lymphoma, and gastric carcinoma. Although in vitro studies have demonstrated that the expression of genes within the cag PAI leads to the activation of a strong host inflammatory response, the functions of mostcag gene products and how they work in concert to promote an immunological response are unknown. We developed a transcriptional reporter that utilizes urease activity and in which nine putative regulatory sequences from the cag PAI were fused to theH. pylori ureB gene. These fusions were introduced in single copies onto the H. pylori chromosome without disruption of the cag PAI. Our analysis indicated that while each regulatory region confers a reproducible amount of promoter activity under laboratory conditions, they differ widely in levels of expression. Transcription initiating upstream of cag15 and upstream of cag21 is induced when the respective fusion strains are cocultured with an epithelial cell monolayer. Results of mouse colonization experiments with an H. pylori strain carrying the cag15-ureB fusion suggested that this putative regulatory region appears to be induced in vivo, demonstrating the importance of the urease reporter as a significant development toward identifying in vivo-induced gene expression in H. pylori.

In vitro and in vivo culture effects on mRNA expression of genes involved in metabolism and apoptosis in bovine embryos

2005 ◽  
Vol 17 (8) ◽  
pp. 775 ◽  
Author(s):  
Hiemke M. Knijn ◽  
Christine Wrenzycki ◽  
Peter J. M. Hendriksen ◽  
Peter L. A. M. Vos ◽  
Elly C. Zeinstra ◽  
...  
Keyword(s):  
Glucose Metabolism ◽  
Mrna Expression ◽  
Critical Period ◽  
Glucose Transporter ◽  
Expression Patterns ◽  
Culture Conditions ◽  
Glut 4 ◽  
Gene Transcripts

Bovine blastocysts produced in vitro differ substantially from their in vivo-derived counterparts with regard to glucose metabolism, level of apoptosis and mRNA expression patterns. Maternal embryonic genomic transition is a critical period in which these changes could be induced. The goals of the present study were twofold: (1) to identify the critical period of culture during which the differences in expression of gene transcripts involved in glucose metabolism are induced; and (2) to identify gene transcripts involved in apoptosis that are differentially expressed in in vitro- and in vivo-produced blastocysts. Relative abundances of transcripts for the glucose transporters Glut-1, Glut-3, Glut-4 and Glut-8, and transcripts involved in the apoptotic cascade, including BAX, BCL-XL, XIAP and HSP 70.1, were analysed by a semiquantitative reverse transcription–polymerase chain reaction assay in single blastocysts produced in vitro or in vivo for specific time intervals, that is, before or after maternal embryonic transition. Whether the culture environment was in vitro or in vivo affected the expression of glucose transporter transcripts Glut-3, Glut-4 and Glut-8. However, the critical period during culture responsible for these changes, before or after maternal embryonic transition, could not be determined. With the exception of XIAP, no effects of culture system on the mRNA expression patterns of BAX, BCL-XL and HSP 70.1 could be observed. These data show that expression of XIAP transcripts in expanded blastocysts is affected by in vitro culture. These findings add to the list of bovine genes aberrantly expressed in culture conditions, but do not support the hypothesis that maternal embryonic transition is critical in inducing the aberrations in gene expression patterns studied here.

Comparison of Vibrio and Firefly Luciferases as Reporter Gene Systems for Use in Bacteria and Plants

1996 ◽  
Vol 23 (1) ◽  
pp. 75 ◽  
Author(s):  
SR Mudge ◽  
WR Lewis-Henderson ◽  
RG Birch
Keyword(s):  
Gene Expression ◽  
Reporter Gene ◽  
Ccd Camera ◽  
Reporter Gene Expression ◽  
In Vitro Assays ◽  
E Coli ◽  
Cell Extracts ◽  
Cooled Ccd

Luciferase genes from Vibrio harveyi (luxAB) and firefly (luc) were introduced into E. coli, Agrobacteriurn, Arabidopsis and tobacco. Transformed bacteria and plants were quantitatively assayed for luciferase activity using a range of in vitro and in vivo assay conditions. Both lux and luc proved efficient reporter genes in bacteria, although it is important to be aware that the sensitive assays may detect expression due to readthrough from distant promoters. LUX activity was undetectable by liquid nitrogen-cooled CCD camera assays on intact tissues of plants which showed strong luxAB expression by in vitro assays. The decanal substrate for the lux assay was toxic to many plant tissues, and caused chemiluminescence in untransformed Arabidopsis leaves. These are serious limitations to application of the lux system for sensitive, non-toxic assays of reporter gene expression in plants. In contrast, LUC activity was readily detectable in intact tissues of all plants with luc expression detectable by luminometer assays on cell extracts. Image intensities of luc-expressing leaves were commonly two to four orders of magnitude above controls under the CCD camera. Provided adequate penetration of the substrate luciferin is obtained, luc is suitable for applications requiring sensitive, non-toxic assays of reporter gene expression in plants.

Changes in the wheat Em 5′ UTR affect reporter gene expression in vivo and in vitro

2001 ◽  
Vol 158 (7) ◽  
pp. 929-934 ◽  
Author(s):  
Manjiri R. Paradkar ◽  
William R. Marcotte
Keyword(s):  
Gene Expression ◽  
Reporter Gene ◽  
Reporter Gene Expression

scholarly journals Functional analysis of haplotypes and promoter activity at the 5' region of the DRD2 gene and associations with schizophrenia.

2020 ◽  
Author(s):  
Xicen Zhang ◽  
Mei Ding ◽  
Yi Liu ◽  
Yongping Liu ◽  
Jiaxin Xing ◽  
...  
Keyword(s):  
Gene Expression ◽  
Cell Lines ◽  
Promoter Region ◽  
Regulatory Region ◽  
Gene Promoter ◽  
Luciferase Reporter ◽  
Drd2 Gene ◽  
Functional Regions

Abstract Background: In previous studies, we researched the association of the DRD2 gene promoter region SNP loci rs7116768, rs1047479195, rs1799732, rs1799978 and schizophrenia using Sanger sequencing. rs7116768 and rs1799978 were found to be slightly associated with schizophrenia. This study investigated the effects of haplotypes consisted of the four SNPs on protein expression level in vitro and identified the functional sequence in the 5’ regulatory region of DRD2 gene which has a potential link with schizophrenia.Methods: Recombinant plasmids with haplotypes, SNPs and 13 recombinant vectors containing deletion fragments from the DRD2 gene 5' regulatory region were transfected into HEK293 and SK-N-SH cell lines. Relative luciferase activity of the haplotypes, SNPs and different sequences was compared using a dual luciferase reporter assay system.Results: Haplotype H4(G-C-InsC-G) could significantly increase the gene expression in SK-N-SH cell lines. Allele C of rs7116768, allele A of rs1047479195 and allele del C of rs1799732 could up-regulate the gene expression. There were 5~7 functional regions in the promoter region of DRD2 gene that could affect the level of gene expression.Conclusion: We cannot rule out the possibility that different haplotypes may influence DRD2 gene expression in vivo. We observed that allele C of rs7116768, allele A of rs1047479195 and allele del C of rs1799732 could up-regulate gene expression. The truncation results confirmed the existence of functional regions in the promoter region of DRD2 gene that could affect the level of gene expression.

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