The role of NeuroD1 in the upregulation of SMYD3 by HBx.

2012 ◽  
Vol 30 (4_suppl) ◽  
pp. 183-183
Author(s):  
Junyao Xu ◽  
Qingqi Hong ◽  
Chuanchao He ◽  
Jie Wang
Keyword(s):  
Gene Expression ◽  
Binding Site ◽  
Promoter Region ◽  
Gene Transfection ◽  
Histone Methyltransferase ◽  
Proximal Promoter ◽  
Luciferase Reporter ◽  
Mobility Shift ◽  
Cis Element ◽  
E Box

183 Background: SET and MYND Domain-Containing Protein 3 (SMYD3) is frequently overexpressed in hepatocellular carcinoma (HCC) exhibiting increased malignant phenotypes. It has also been known that the hepatitis B virus x protein (HBx) is strongly associated with HCC development and progression. Although overexpression of both proteins is related to HCC, the relationship between the two has not been well studied. Methods: Immunohistochemical staining was used to detect the expression of HBx and SMYD3 in HCC tumor tissues. HBx gene transfection, RNAi, and histone methyltransferase(H3-K4) activity assay were performed to reveal the transcrpitionally activation of HBx on functional SMYD3 gene expression. Chromatin immunoprecipitation (ChIP), Co-immunoprecipitation (Co-IP), Electrophoretic mobility shift assay (EMSA) were applied to investigate the underlying mechanism. Dual-luciferase reporter assay was used to search for the HBx responsive cis-element of SMYD3 gene. Results: Immunohistochemistry identified the positive correlation between HBx and SMYD3 expression in 42 HCC tissues. Up-regulation of HBx on SMYD3 expression was validated through experiments involving overexpression or knock-down of HBx in different HCC cell lines. And up-regulated SMYD3 is functionally active as histone methyltransferase. Next we found that HBx transcriptionally regulated SMYD3 gene expression by interacting with RNA polymerase IIand altering its binding site to a proximal promoter region(SD2) from a distant promoter region(SD6) of SMYD3. Truncated and mutant reporter assays revealed that the cis-element mapped in -178~-203bp in SMYD3 promotor is responsive for HBx-transactivation. And this 25bp cis-element contains a E-box 3 unit, which is a binding site for the transcriptional factor Neurogenic differentiation 1(NeuroD1). EMSA and Chip showed that HBx increased NeuroD1 binding to SMYD3 proximal promotor, however transcient expression of antisense NeuroD1 abolished HBx-induced SMYD3 expression. Conclusions: HBx transcriptionally up-regulates SMYD3 and that this process is mediated by NeuroD1 through binding to the E-box 3 site of SMYD3 promotor.

scholarly journals DEC1 Modulates the Circadian Phase of Clock Gene Expression

2008 ◽  
Vol 28 (12) ◽  
pp. 4080-4092 ◽  
Author(s):  
Ayumu Nakashima ◽  
Takeshi Kawamoto ◽  
Kiyomasa K. Honda ◽  
Taichi Ueshima ◽  
Mitsuhide Noshiro ◽  
...  
Keyword(s):  
Gene Expression ◽  
Clock Genes ◽  
Luciferase Reporter ◽  
Constant Darkness ◽  
Mobility Shift ◽  
Behavioral Rhythms ◽  
Circadian Phase ◽  
Clock Gene Expression ◽  
E Box ◽  
E Boxes

ABSTRACT DEC1 suppresses CLOCK/BMAL1-enhanced promoter activity, but its role in the circadian system of mammals remains unclear. Here we examined the effect of Dec1 overexpression or deficiency on circadian gene expression triggered with 50% serum. Overexpression of Dec1 delayed the phase of clock genes such as Dec1, Dec2, Per1, and Dbp that contain E boxes in their regulatory regions, whereas it had little effect on the circadian phase of Per2 and Cry1 carrying CACGTT E′ boxes. In contrast, Dec1 deficiency advanced the phase of the E-box-containing clock genes but not that of the E′-box-containing clock genes. Accordingly, DEC1 showed strong binding and transrepression on the E box, but not on the E′ box, in chromatin immunoprecipitation, electrophoretic mobility shift, and luciferase reporter assays. Dec1 −/− mice showed behavioral rhythms with slightly but significantly longer circadian periods under conditions of constant darkness and faster reentrainment to a 6-h phase-advanced shift of a light-dark cycle. Knockdown of Dec2 with small interfering RNA advanced the phase of Dec1 and Dbp expression, and double knockdown of Dec1 and Dec2 had much stronger effects on the expression of the E-box-containing clock genes. These findings suggest that DEC1, along with DEC2, plays a role in the finer regulation and robustness of the molecular clock.

scholarly journals Regulation of lactase–phlorizin hydrolase gene expression by the caudal-related homoeodomain protein Cdx-2

1997 ◽  
Vol 322 (3) ◽  
pp. 833-838 ◽  
Author(s):  
Jesper T. TROELSEN ◽  
Cathy MITCHELMORE ◽  
Nikolaj SPODSBERG ◽  
Anette M. JENSEN ◽  
Ove NORÉN ◽  
...  
Keyword(s):  
Gene Expression ◽  
Small Intestine ◽  
Binding Site ◽  
Electrophoretic Mobility Shift Assay ◽  
Gene Transcription ◽  
Transcriptional Activity ◽  
Nuclear Factor ◽  
Mobility Shift ◽  
Cis Element ◽  
Mobility Shift Assay

Lactase–phlorizin hydrolase is exclusively expressed in the small intestine and is often used as a marker for the differentiation of enterocytes. The cis-element CE-LPH1 found in the lactase–phlorizin hydrolase promoter has previously been shown to bind an intestinal-specific nuclear factor. By electrophoretic mobility-shift assay it was shown that the factor Cdx-2 (a homoeodomain-protein related to caudal) binds to a TTTAC sequence in the CE-LPH1. Furthermore it was demonstrated that Cdx-2 is able to activate reporter gene transcription by binding to CE-LPH1. A mutation in CE-LPH1, which does not affect Cdx-2 binding, results in a higher transcriptional activity, indicating that the CE-LPH1 site contains other binding site(s) in addition to the Cdx-2-binding site.

scholarly journals Identification of a signal transducer and activator of transcription (STAT) binding site in the mouse metallothionein-I promoter involved in interleukin-6-induced gene expression

1998 ◽  
Vol 337 (1) ◽  
pp. 59-65 ◽  
Author(s):  
Dae Kee LEE ◽  
Javier CARRASCO ◽  
Juan HIDALGO ◽  
Glen K. ANDREWS
Keyword(s):  
Gene Expression ◽  
Binding Site ◽  
Time Course ◽  
Proximal Promoter ◽  
Type I ◽  
Mobility Shift ◽  
Knock Out ◽  
I Gene

Mechanisms of regulation of mouse metallothionein (MT)-I gene expression in response to bacterial endotoxin-lipopolysaccharide (LPS) were examined. Northern blot analysis of hepatic MT-I mRNA in interleukin (IL)-6 or tumour necrosis factor (TNF)-receptor type I knock-out mice demonstrated that IL-6, not TNF-α, is of central importance in mediating hepatic MT-I gene expression in vivo after LPS injection. In vivo genomic footprinting of the MT-I promoter demonstrated a rapid increase, after LPS injection, in the protection of several guanine residues in the -250 to -300 bp region of the MT-I promoter. The protected bases were within sequences which resemble binding sites for the signal transducers and activators of transcription (STAT) transcription factor family. Electrophoretic mobility-shift assays using oligonucleotides from footprinted MT-I promoter regions showed that injection of LPS resulted in a rapid increase in the specific, high-affinity, in vitro binding of STAT1 and STAT3 to a binding site at -297 bp (TTCTCGTAA). Western blotting of hepatic nuclear proteins showed that the time-course for changes of total nuclear STAT1 and STAT3 after LPS injection paralleled the increased complex formation in vitro using this oligonucleotide, and binding was specifically competed for by a functional STAT-binding site from the rat α2-macroglobulin promoter. Furthermore, the MT-I promoter -297 bp STAT-binding site conferred IL-6 responsiveness in the context of a minimal promoter in transient transfection assays using HepG2 cells. This study suggests that the effects of LPS on hepatic MT-I gene expression are mediated by IL-6 and involve the activation of STAT-binding to the proximal promoter.

MyoD promotes porcine PPARγ gene expression through an E-box and a MyoD-binding site in the PPARγ promoter region

2016 ◽  
Vol 365 (2) ◽  
pp. 381-391 ◽  
Author(s):  
Bing Deng ◽  
Feng Zhang ◽  
Kun Chen ◽  
Jianghui Wen ◽  
Haijun Huang ◽  
...  
Keyword(s):  
Gene Expression ◽  
Binding Site ◽  
Promoter Region ◽  
E Box ◽  
Pparγ Gene

scholarly journals Upstream stimulatory factor 1 activates GATA5 expression through an E-box motif

2012 ◽  
Vol 446 (1) ◽  
pp. 89-98 ◽  
Author(s):  
Bohao Chen ◽  
Rona Hsu ◽  
Zhenping Li ◽  
Paul C. Kogut ◽  
Qingxia Du ◽  
...  
Keyword(s):  
Gene Expression ◽  
Promoter Hypermethylation ◽  
Site Directed Mutagenesis ◽  
Luciferase Reporter ◽  
Upstream Stimulatory Factor ◽  
Mobility Shift ◽  
Reverse Transcription Pcr ◽  
E Box ◽  
Upstream Stimulatory Factor 1 ◽  
Stimulatory Factor

Silencing of GATA5 gene expression as a result of promoter hypermethylation has been observed in lung, gastrointestinal and ovarian cancers. However, the regulation of GATA5 gene expression has been poorly understood. In the present study, we have demonstrated that an E (enhancer)-box in the GATA5 promoter (bp −118 to −113 in mice; bp −164 to −159 in humans) positively regulates GATA5 transcription by binding USF1 (upstream stimulatory factor 1). Using site-directed mutagenesis, EMSA (electrophoretic mobility-shift analysis) and affinity chromatography, we found that USF1 specifically binds to the E-box sequence (5′-CACGTG-3′), but not to a mutated E-box. CpG methylation of this E-box significantly diminished its binding of transcription factors. Mutation of the E-box within a GATA5 promoter fragment significantly decreased promoter activity in a luciferase reporter assay. Chromatin immunoprecipitation identified that USF1 physiologically interacts with the GATA5 promoter E-box in mouse intestinal mucosa, which has the highest GATA5 gene expression in mouse. Co-transfection with a USF1 expression plasmid significantly increased GATA5 promoter-driven luciferase transcription. Furthermore, real-time and RT (reverse transcription)–PCR analyses confirmed that overexpression of USF1 activates endogenous GATA5 gene expression in human bronchial epithelial cells. The present study provides the first evidence that USF1 activates GATA5 gene expression through the E-box motif and suggests a potential mechanism (disruption of the E-box) by which GATA5 promoter methylation reduces GATA5 expression in cancer.

Hepatocyte nuclear factor-4 regulates intestinal expression of the guanylin/heat-stable toxin receptor

1999 ◽  
Vol 276 (3) ◽  
pp. G728-G736 ◽  
Author(s):  
E. Scott Swenson ◽  
Elizabeth A. Mann ◽  
M. Lynn Jump ◽  
Ralph A. Giannella
Keyword(s):  
Binding Site ◽  
Expression Vector ◽  
Proximal Promoter ◽  
Luciferase Reporter ◽  
Surface Epithelium ◽  
Nuclear Factor ◽  
Hepatocyte Nuclear Factor ◽  
T84 Cells ◽  
Mobility Shift ◽  
Hepatocyte Nuclear Factor 4

We have investigated the regulation of gene transcription in the intestine using the guanylyl cyclase C (GCC) gene as a model. GCC is expressed in crypts and villi in the small intestine and in crypts and surface epithelium of the colon. DNase I footprint, electrophoretic mobility shift assay (EMSA), transient transfection assays, and mutagenesis experiments demonstrated that GCC transcription is regulated by a critical hepatocyte nuclear factor-4 (HNF-4) binding site between bp −46 and −29 and that bp −38 to −36 were essential for binding. Binding of HNF-4 to the GCC promoter was confirmed by competition EMSA and by supershift EMSA. In Caco-2 and T84 cells, which express both GCC and HNF-4, the activity of GCC promoter and/or luciferase reporter plasmids containing 128 or 1973 bp of 5′-flanking sequence was dependent on the HNF-4 binding site in the proximal promoter. In COLO-DM cells, which express neither GCC nor HNF-4, cotransfection of GCC promoter/luciferase reporter plasmids with an HNF-4 expression vector resulted in 23-fold stimulation of the GCC promoter. Mutation of the HNF-4 binding site abolished this transactivation. Transfection of COLO-DM cells with the HNF-4 expression vector stimulated transcription of the endogenous GCC gene as well. These results indicate that HNF-4 is a key regulator of GCC expression in the intestine.

Cell-specific regulation of IRS-1 gene expression: role of E box and C/EBP binding site in HepG2 cells and CHO cells

Diabetes ◽  
1997 ◽  
Vol 46 (3) ◽  
pp. 354-362 ◽  
Author(s):  
K. Matsuda ◽  
E. Araki ◽  
R. Yoshimura ◽  
K. Tsuruzoe ◽  
N. Furukawa ◽  
...  
Keyword(s):  
Gene Expression ◽  
Binding Site ◽  
Cho Cells ◽  
Hepg2 Cells ◽  
E Box ◽  
Specific Regulation

scholarly journals Regulation of Swarming Motility and flhDCSm Expression by RssAB Signaling in Serratia marcescens

2008 ◽  
Vol 190 (7) ◽  
pp. 2496-2504 ◽  
Author(s):  
Po-Chi Soo ◽  
Yu-Tze Horng ◽  
Jun-Rong Wei ◽  
Jwu-Ching Shu ◽  
Chia-Chen Lu ◽  
...  
Keyword(s):  
Serratia Marcescens ◽  
Binding Site ◽  
Promoter Region ◽  
Transcriptional Start Site ◽  
Direct Interaction ◽  
Underlying Mechanism ◽  
Inhibitory Effect ◽  
Start Codon ◽  
Mobility Shift

ABSTRACT Serratia marcescens cells swarm at 30°C but not at 37°C, and the underlying mechanism is not characterized. Our previous studies had shown that a temperature upshift from 30 to 37°C reduced the expression levels of flhDCSm and hagSm in S. marcescens CH-1. Mutation in rssA or rssB, cognate genes that comprise a two-component system, also resulted in precocious swarming phenotypes at 37°C. To further characterize the underlying mechanism, in the present study, we report that expression of flhDCSm and synthesis of flagella are significantly increased in the rssA mutant strain at 37°C. Primer extension analysis for determination of the transcriptional start site(s) of flhDCSm revealed two transcriptional start sites, P1 and P2, in S. marcescens CH-1. Characterization of the phosphorylated RssB (RssB∼P) binding site by an electrophoretic mobility shift assay showed direct interaction of RssB∼P, but not unphosphorylated RssB [RssB(D51E)], with the P2 promoter region. A DNase I footprinting assay using a capillary electrophoresis approach further determined that the RssB∼P binding site is located between base pair positions −341 and −364 from the translation start codon ATG in the flhDCSm promoter region. The binding site overlaps with the P2 “−35” promoter region. A modified chromatin immunoprecipitation assay was subsequently performed to confirm that RssB∼P binds to the flhDCSm promoter region in vivo. In conclusion, our results indicated that activated RssA-RssB signaling directly inhibits flhDCSm promoter activity at 37°C. This inhibitory effect was comparatively alleviated at 30°C. This finding might explain, at least in part, the phenomenon of inhibition of S. marcescens swarming at 37°C.

AVP-induced VIT32 gene expression in collecting duct cells occurs via trans-activation of a CRE in the 5′-flanking region of the VIT32 gene

2004 ◽  
Vol 287 (3) ◽  
pp. F460-F468 ◽  
Author(s):  
Christie P. Thomas ◽  
Randy W. Loftus ◽  
Kang Z. Liu
Keyword(s):  
Gene Expression ◽  
Promoter Region ◽  
Collecting Duct ◽  
Airway Epithelial Cells ◽  
Proximal Promoter ◽  
Xenopus Laevis Oocytes ◽  
Proximal Promoter Region ◽  
Duct Cells ◽  
Collecting Duct Cells ◽  
Flanking Region

VIT32, a vasopressin-induced transcript, inhibits Na+ transport when coexpressed with the epithelial sodium channel in Xenopus laevis oocytes ( EMBO J 21: 5109–5117, 2002). To understand the mechanism of VIT32 gene regulation, we examined the effect of DDAVP and cAMP stimulation on VIT32 expression in M-1 mouse collecting duct cells and in H441 human airway epithelial cells. Elevation of cAMP with forskolin and IBMX increased VIT32 gene expression with a peak effect at 2 h. The increase in gene expression was abolished by H89 and by actinomycin D, suggesting that cAMP stimulates VIT32 mRNA expression by a PKA-mediated increase in gene transcription. An ∼1.5-kb fragment of the 5′-flanking region of VIT32 was cloned and was able to confer cAMP-stimulated reporter gene activity when transfected into M-1 and H441 cells. By deletion analysis and site-directed mutagenesis, a cAMP response element (CRE) was identified within the proximal promoter region that was sufficient to account for the increase in VIT32 gene expression seen with DDAVP and elevation of cAMP. Furthermore, DDAVP-stimulated VIT32 promoter-reporter activity was inhibited by H89 and by a dominant negative CREB construct. Finally, we were able to identify CREB as a nuclear protein that bound to the VIT32 CRE in gel mobility shift assays. In summary, DDAVP stimulates transcription of VIT32 via a CRE within the proximal promoter region of the VIT32 gene.

scholarly journals Promoter analysis of the DHCR24 (3β-hydroxysterol Δ24-reductase) gene: characterization of SREBP (sterol-regulatoryelement-binding protein)-mediated activation

2012 ◽  
Vol 33 (1) ◽  
Author(s):  
Lidia A. Daimiel ◽  
María E. Fernández-Suárez ◽  
Sara Rodríguez-Acebes ◽  
Lorena Crespo ◽  
Miguel A. Lasunción ◽  
...  
Keyword(s):  
Cellular Response ◽  
Binding Protein ◽  
Regulatory Element ◽  
Cholesterol Biosynthesis ◽  
Regulatory Elements ◽  
Proximal Promoter ◽  
Luciferase Reporter ◽  
Mobility Shift ◽  
Gene Characterization ◽  
Cis Acting

DHCR24 (3β-hydroxysterol Δ24-reductase) catalyses the reduction of the C-24 double bond of sterol intermediates during cholesterol biosynthesis. DHCR24 has also been involved in cell growth, senescence and cellular response to oncogenic and oxidative stress. Despite its important roles, little is known about the transcriptional mechanisms controlling DHCR24 gene expression. We analysed the proximal promoter region and the cholesterol-mediated regulation of DHCR24. A putative SRE (sterol-regulatory element) at −98/−90 bp of the transcription start site was identified. Other putative regulatory elements commonly found in SREBP (SRE-binding protein)-targeted genes were also identified. Sterol responsiveness was analysed by luciferase reporter assays of approximately 1 kb 5′-flanking region of the human DHCR24 gene in HepG2 and SK-N-MC cells. EMSAs (electrophoretic mobility-shift assays) and ChIP (chromatin immunoprecipitation) assays demonstrated cholesterol-dependent recruitment and binding of SREBPs to the putative SRE. Given the presence of several CACCC-boxes in the DHCR24 proximal promoter, we assessed the role of KLF5 (Krüppel-like factor 5) in androgen-regulated DHCR24 expression. DHT (dihydrotestosterone) increased DHCR24 expression synergistically with lovastatin. However, DHT was unable to activate the DHCR24 proximal promoter, whereas KLF5 did, indicating that this mechanism is not involved in the androgen-induced stimulation of DHCR24 expression. The results of the present study allow the elucidation of the mechanism of regulation of the DHCR24 gene by cholesterol availability and identification of other putative cis-acting elements which may be relevant for the regulation of DHCR24 expression.

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