scholarly journals Transcriptional Activation of E2F1 Gene Expression by 17β-Estradiol in MCF-7 Cells Is Regulated by NF-Y-Sp1/Estrogen Receptor Interactions

1999 ◽  
Vol 13 (8) ◽  
pp. 1373-1387 ◽  
Author(s):  
Weili Wang ◽  
Lian Dong ◽  
Brad Saville ◽  
Stephen Safe
Keyword(s):  
Gene Expression ◽  
Estrogen Receptor ◽  
Dna Binding ◽  
Transcriptional Activation ◽  
Gene Promoter ◽  
Proximal Region ◽  
Mobility Shift ◽  
Protein Levels ◽  
17Β Estradiol ◽  
Mcf 7

Abstract 17β-Estradiol (E2) stimulated proliferation and DNA synthesis in MCF-7 human breast cancer cells, and this was accompanied by induction of E2F1 mRNA and protein levels. Analysis of the E2F1 gene promoter showed that the −146 to− 54 region was required for E2-responsiveness in transient transfection assays, and subsequent deletion/mutation analysis showed that a single upstream GC-rich and two downstream CCAAT-binding sites were required for transactivation by E2. Gel mobility shift assays with multiple oligonucleotides and protein antibodies (for supershifts) showed that the −146 to −54 region of the E2F1 gene promoter bound Sp1 and NF-Y proteins in MCF-7 cells. The estrogen receptor (ER) protein enhanced Sp1 interactions with upstream GC-rich sites, and interactions of ER, Sp1, and ER/Sp1 with downstream DNA bound-NF-Y was investigated by kinetic analysis for protein-DNA binding (on- and off-rates), coimmunoprecipitation, and pulldown assays using wild-type and truncated glutathione S-transferase (GST)-Sp1 chimeric proteins. The results showed that Sp1 protein enhanced the Bmax of NF-Y-DNA binding by more than 5-fold (on-rate); in addition, the Sp1-enhanced NF-Y-DNA complex was further stabilized by coincubation with ER and the rate of dissociation (t1/2) was decreased by approximately 50%. Sp1 antibodies immunoprecipitated [35S]NF-YA after coincubation with unlabeled Sp1 protein. Thus, transcriptional activation of E2F1 gene expression in MCF-7 cells by E2 is regulated by multiprotein ER/Sp1-NF-Y interactions at GC-rich and two CCAAT elements in the proximal region of the E2F1 gene promoter. This represents a unique trans-acting protein complex in which ligand-dependent transactivation by the ER is independent of direct ER interactions with promoter elements.

scholarly journals Transcriptional Activation of Insulin-Like Growth Factor-Binding Protein-4 by 17β-Estradiol in MCF-7 Cells: Role of Estrogen Receptor-Sp1 Complexes*

Endocrinology ◽  
1999 ◽  
Vol 140 (6) ◽  
pp. 2501-2508 ◽  
Author(s):  
Chunhua Qin ◽  
Pomila Singh ◽  
Stephen Safe
Keyword(s):  
Gene Expression ◽  
Estrogen Receptor ◽  
Growth Factor ◽  
Binding Protein ◽  
Gene Promoter ◽  
Insulin Like Growth Factor ◽  
Factor Binding ◽  
Human Estrogen Receptor ◽  
17Β Estradiol ◽  
Mcf 7

Abstract Insulin-like growth factor-binding protein-4 (IGFBP-4) is expressed in MCF-7 human breast cancer cells, and treatment of these cells with 17β-estradiol (E2) resulted in induction of IGFBP-4 gene expression (>3-fold) and protein secretion (>6-fold). To identify genomic sequences associated with E2 responsiveness, the 5′-promoter region (−1214 to +18) of the IGFBP-4 gene was cloned into a vector upstream from the firefly luciferase reporter gene, and E2 induced a 10-fold increase in luciferase activity in MCF-7 cells transiently transfected with this construct. Deletion analysis of this region of the IGFBP-4 gene promoter identified two GC-rich sequences at −559 to −553 and −72 to −64 that were important for E2-induced trans-activation. Gel mobility shift assays using 32P-labeled −569 to −540 and −83 to −54 oligonucleotides from the IGFBP-4 gene promoter showed that Sp1 protein bound these oligonucleotides to form a retarded band, and the intensity of the band was competitively decreased after coincubation with unlabeled IGFBP-4-derived and consensus Sp1 oligonucleotides. Mutation of the GC-rich sites within these sequences resulted in loss of the retarded band formation. Wild-type human estrogen receptor did not bind directly to the IGFBP-4 oligonucleotides; however, human estrogen receptor enhanced Sp1-DNA binding in a concentration-dependent manner. The results of this study demonstrate that at least two GC-rich sequences at −559 to −553 and− 72 to −64 are required for induction of IGFBP-4 gene expression by E2 in MCF-7 cells.

scholarly journals PARP7 and Mono-ADP-Ribosylation Negatively Regulate Estrogen Receptor α Signaling in Human Breast Cancer Cells

Cells ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 623
Author(s):  
Marit Rasmussen ◽  
Susanna Tan ◽  
Venkata S. Somisetty ◽  
David Hutin ◽  
Ninni Elise Olafsen ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Estrogen Receptor ◽  
Protein Modification ◽  
Target Genes ◽  
Estrogen Receptor Α ◽  
Transactivation Domain ◽  
Adp Ribosylation ◽  
Protein Levels ◽  
17Β Estradiol ◽  
Mcf 7

ADP-ribosylation is a post-translational protein modification catalyzed by a family of proteins known as poly-ADP-ribose polymerases. PARP7 (TIPARP; ARTD14) is a mono-ADP-ribosyltransferase involved in several cellular processes, including responses to hypoxia, innate immunity and regulation of nuclear receptors. Since previous studies suggested that PARP7 was regulated by 17β-estradiol, we investigated whether PARP7 regulates estrogen receptor α signaling. We confirmed the 17β-estradiol-dependent increases of PARP7 mRNA and protein levels in MCF-7 cells, and observed recruitment of estrogen receptor α to the promoter of PARP7. Overexpression of PARP7 decreased ligand-dependent estrogen receptor α signaling, while treatment of PARP7 knockout MCF-7 cells with 17β-estradiol resulted in increased expression of and recruitment to estrogen receptor α target genes, in addition to increased proliferation. Co-immunoprecipitation assays revealed that PARP7 mono-ADP-ribosylated estrogen receptor α, and mass spectrometry mapped the modified peptides to the receptor’s ligand-independent transactivation domain. Co-immunoprecipitation with truncated estrogen receptor α variants identified that the hinge region of the receptor is required for PARP7-dependent mono-ADP-ribosylation. These results imply that PARP7-mediated mono-ADP-ribosylation may play an important role in estrogen receptor positive breast cancer.

scholarly journals Transcriptional Activation of Deoxyribonucleic Acid Polymerase α Gene Expression in MCF-7 Cells by 17β-Estradiol*

Endocrinology ◽  
2001 ◽  
Vol 142 (3) ◽  
pp. 1000-1008 ◽  
Author(s):  
Ismael Samudio ◽  
Carrie Vyhlidal ◽  
Fan Wang ◽  
Matthew Stoner ◽  
Ichen Chen ◽  
...  
Keyword(s):  
Gene Expression ◽  
Transcriptional Activation ◽  
Deoxyribonucleic Acid ◽  
17Β Estradiol ◽  
Mcf 7

scholarly journals A natural sequence consisting of overlapping glucocorticoid-responsive elements mediates glucocorticoid, but not androgen, regulation of gene expression

2000 ◽  
Vol 350 (1) ◽  
pp. 123-129 ◽  
Author(s):  
Charbel MASSAAD ◽  
Michèle GARLATTI ◽  
Elizabeth M. WILSON ◽  
Françoise CADEPOND ◽  
Robert BAROUKI
Keyword(s):  
Gene Expression ◽  
Thymidine Kinase ◽  
Transcriptional Activation ◽  
Regulation Of Gene Expression ◽  
Gene Promoter ◽  
Mobility Shift ◽  
Liver And Kidney ◽  
Androgen Regulation ◽  
Responsive Element ◽  
Half Site

Cytosolic aspartate aminotransferase (cAspAT) is regulated by glucocorticoids in rat liver and kidney. Part of this regulation is mediated by an unusual glucocorticoid-responsive element (GRE)-like sequence called GRE A. GRE A is composed of two overlapping imperfect GREs, each comprising a conserved half-site (half-sites 1 and 4 respectively) and a poorly conserved half-site (half-sites 2 and 3 respectively). The sequence binds co-operatively two dimers of the glucocorticoid receptor (GR) and mediates efficient glucocorticoid regulation of gene expression. Analysis of deletions of the cAspAT gene promoter and subcloning of GRE A upstream of the thymidine kinase promoter indicate that this sequence is responsive to glucocorticoids, but not to androgens. Electrophoretic mobility shift assays indicate that the GRE A unit does not bind the androgen receptor (AR). The modification of three nucleotides in the poorly conserved half-sites 2 and 3, converting GRE A into two overlapping high-affinity GREs (ov-cGRE), resulted in co-operative binding of the AR. Furthermore, ov-cGRE efficiently mediated androgen regulation of the thymidine kinase promoter. A single base modification in half-site 2 or 3 in GRE A allowed the binding of the AR as one or two dimers respectively, and restored transcriptional activation by androgens only in the latter case. Thus the poor affinity of the AR for half-sites 2 and 3 prevented its binding to GRE A, indicating that the overlapping GRE A sequence of the cAspAT gene promoter discriminates a glucocorticoid-mediated from an androgen-mediated response.

scholarly journals Cell Context-Dependent Differences in the Induction of E2F-1 Gene Expression by 17β-Estradiol in MCF-7 and ZR-75 Cells

Endocrinology ◽  
2003 ◽  
Vol 144 (5) ◽  
pp. 1675-1685 ◽  
Author(s):  
Sharon Ngwenya ◽  
Stephen Safe
Keyword(s):  
Breast Cancer ◽  
Gene Expression ◽  
Chimeric Protein ◽  
Gene Promoter ◽  
Estrogen Receptor Α ◽  
Breast Cancer Cell Lines ◽  
Er Positive ◽  
17Β Estradiol ◽  
Positive Breast Cancer Cell ◽  
Mcf 7

17β-Estradiol (E2) induces E2F-1 gene expression in ZR-75 and MCF-7 human breast cancer cells. Analysis of the E2F-1 gene promoter in MCF-7 cells previously showed that hormone-induced transactivation required interactions between estrogen receptor α (ERα)/Sp1 bound to upstream GC-rich sites and NFYA bound to downstream CCAAT sites within the −169 to −54 region of the promoter. This same region of the E2F-1 promoter was also E2 responsive in ERα-positive ZR-75 cells; however, further analysis of the promoter showed that cooperative ERα/Sp1/NFY interactions were not necessary for hormone-induced transactivation in ZR-75 cells. The upstream GC-rich motifs (−169 to −111) are activated independently by ERα/Sp1 in ZR-75 but not MCF-7 cells, and a construct (pE2F-1jm1) containing the −122 to −54 downstream CCAAT site that bound NFYA was also E2 responsive. E2 also induced reporter gene activity in ZR-75 cells transfected with an expression plasmid for a chimeric protein containing the DNA-binding domain of the yeast GAL4 protein fused to NFYA (pM-NFYA) and a construct containing five tandem GAL4 response elements. Subsequent studies showed that hormonal activation of pE2F-1jm1 and pM-NFYA are dependent on nongenomic pathways in which E2 activates cAMP/protein kinase A. Hormone-dependent regulation of E2F-1 gene expression in ZR-75 and MCF-7 involves the same cis elements and interacting transcription factors but different mechanisms, demonstrating the importance of cell context on transactivation pathways, even among ER-positive breast cancer cell lines.

Intracellular HMGB1 Transactivates the Human IL1B Gene Promoter through Association with an ETS Transcription Factor PU.1.

Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 1271-1271
Author(s):  
Junichi Tsukada ◽  
Fumihiko Mouri ◽  
Takamitsu Mizobe ◽  
Takehiro Higashi ◽  
Hiroto Izumi ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Dna Binding ◽  
Transcriptional Activation ◽  
Proinflammatory Cytokine ◽  
Expression Vector ◽  
High Mobility ◽  
Gene Promoter ◽  
Physical Interaction ◽  
Chromosomal Protein ◽  
Mobility Shift

Abstract High mobility group box chromosomal protein 1 (HMGB1) was recently identified as a late proinflammatory mediator of endotoxin lethality, which amplifies and sustains the inflammatory processes via macrophage/monocyte activation by extracellular release of HMGB1. However, it was originally described as a nonhistone nuclear protein to bind and distort the structure of DNA and to regulate transcription through association with several transcription factors. Here we investigated the effect of intracellular HMGB1 on transcriptional gene regulation of an immediate early proinflammatory cytokine IL-1β in transient transfection studies using HMGB1 expression vector (pcDNA3HMGB1) and murine macrophage cells RAW264.7. When pcDNA3HMGB1 was introduced into RAW264.7 cells with pGL3HT reporter containing the -131 to +12 minimal IL-1β gene promoter, IL-1β promoter activity was significantly induced by expression of HMGB1. The gene promoter possesses two important transcription factor binding motifs, one for PU.1, a myeloid and B cell-specific transcription factor that belongs to the ETS family, and the other a binding site for NF-IL6. To verify the functional role of intracellular HMGB1 in transactivation of the IL-1β promoter, a PU.1 expression vector and/or pcDNA3HMGB1 were cotransfected into PU.1-deficient murine thymocytes EL4 cells along with pGL3HT reporter. As a result, HMGB1 synergized with PU.1 to transactivate the IL-1β promoter, but not HMGB1 alone. This argument was supported by our GST-pulldown data, which demonstrated direct physical interaction of HMGB1 with PU.1. In addition, deletion of the PU.1 winged helix-turn-helix DNA-binding domain significantly inhibited the association of PU.1 with HMGB1. To determine whether HMGB1 could affect PU.1 DNA-binding affinity, we performed electrophoretic mobility shift assay using a radiolabeled IL-1β -59 to +12 promoter element (DT), recombinant PU.1 (rPU.1) and GST-HMGB1. Two complexes with slower and faster mobilities were generated by the addition of HMGB1 to a mixture of rPU.1 and DT probe. The two complexes were abrogated by preincubation with anti-PU.1 Ab, while anti-HMGB1 Ab reacted only with the complex with a slower mobility, indicating that the complex with a slower mobility formed by addition of HMGB1 contained both HMGB1 and PU.1, while the band with a faster mobility contained only PU.1. From the present study, we propose that intracellular HMGB1 might function as a coactivator in PU.1-mediated transcriptional activation, which facilitate access of PU.1 to specific DNA targets. The fact that PU.1 is a transcription factor essential to macrophages/monocyte-specific proinflammatory cytokine genes further raise the possibility that interaction of PU.1 with HMGB1 may play an important role in the inflammation cascade in macrophages/monocytes.

scholarly journals Sequential Action of Ets-1 and Sp1 in the Activation of the Human β-1,4-Galactosyltransferase V Gene Involved in Abnormal Glycosylation Characteristic of Cancer Cells

2007 ◽  
Vol 282 (38) ◽  
pp. 27702-27712 ◽  
Author(s):  
Takeshi Sato ◽  
Kiyoshi Furukawa
Keyword(s):  
Gene Expression ◽  
Binding Site ◽  
Cancer Cells ◽  
Transcriptional Activation ◽  
Promoter Activity ◽  
A549 Cells ◽  
Gene Promoter ◽  
Dominant Negative ◽  
Mobility Shift ◽  
V Gene

Malignant transformation is associated with increased gene expression of β-1,4-galactosyltransferase (β-1,4-GalT) V, which contributes to the biosynthesis of highly branched N-linked oligosaccharides characteristic of cancer cells. Our previous study showed that expression of the human β-1,4-GalT V gene is regulated by Sp1 (Sato, T., and Furukawa, K. (2004) J. Biol. Chem. 279, 39574–39583), and a subsequent study showed that the gene expression is also activated by Ets-1, a product of the oncogene (Sato, T., and Furukawa, K. (2005) Glycoconj. J. 22, 365). Herein we report the mechanism of β-1,4-GalT V gene activation by these transcription factors. The gene expression and promoter activity of β-1,4-GalT V increased when the ets-1 cDNA was transfected into A549 cells, which contain a small amount of Ets-1, but decreased dramatically when the dominant-negative ets-1 cDNA was transfected into HepG2 cells, which contain a large amount of Ets-1. Luciferase assays using deletion constructs of the β-1,4-GalT V gene promoter showed that promoter region –116 to +22 is critical for the transcriptional activation of the gene by Ets-1. Despite the presence of one Ets-1-binding site, which overlapped the Sp1-binding site, electrophoretic mobility shift assays showed that the region bound preferentially to Sp1 rather than to Ets-1. To solve this problem, we examined the transcriptional regulation of the human Sp1 gene by Ets-1 and found that the gene expression and promoter activity of Sp1 are regulated by Ets-1 in cancer cells. Functional analyses of two Ets-1-binding sites in the Sp1 gene promoter showed that only Ets-1-binding site –413 to –404 is involved in the activation of the gene by Ets-1. These results indicate that Ets-1 enhances expression of the β-1,4-GalT V gene through activation of the Sp1 gene in cancer cells.

scholarly journals Activation of adenosine deaminase in MCF-7 cells through IGF-estrogen receptor alpha crosstalk

2001 ◽  
Vol 26 (3) ◽  
pp. 217-228 ◽  
Author(s):  
W Xie ◽  
R Duan ◽  
S Safe
Keyword(s):  
Gene Expression ◽  
Estrogen Receptor ◽  
Adenosine Deaminase ◽  
Estrogen Receptor Alpha ◽  
Gene Promoter ◽  
Mapk Signaling ◽  
Dominant Negative ◽  
Mitogen Activated Protein Kinase ◽  
Receptor Alpha ◽  
Mcf 7

Adenosine deaminase (ADA) regulates cellular levels of adenosine and deoxyadenosine, and 17beta-estradiol (E(2)) induces ADA mRNA in MCF-7 human breast cancer cells. IGF-I also induces ADA gene expression in these cells, and induction of this response through IGF activation of estrogen receptor alpha (ERalpha) was further investigated. IGF and other polypeptide growth factors induce reporter gene expression in MCF-7 cells cotransfected with ERalpha expression plasmid and pADA211, a construct containing the -211 to +11 region of the ADA gene promoter which is required for high basal and E(2)-inducible activity. Deletion analysis of this promoter demonstrates that IGF activates ERalpha/Sp1 interactions with multiple GC-rich sites in the promoter and this response is abrogated in cells transfected with ERalpha containing mutations at Ser(118) or Ser(163). IGF induces both MAPK (mitogen-activated protein kinase) and PI3-K (phosphatidylinositol-3-kinase) phosphorylation cascades in MCF-7 cells; however, using a series of inhibitors and dominant negative constructs, our results show that induction of ADA by IGF activation of ERalpha/Sp1 is dependent on the MAPK signaling pathway.

scholarly journals The Zinc Finger-Containing Transcription Factor Gata-4 Is Expressed in the Developing Endocrine Pancreas and Activates Glucagon Gene Expression

2005 ◽  
Vol 19 (3) ◽  
pp. 759-770 ◽  
Author(s):  
Beate Ritz-Laser ◽  
Aline Mamin ◽  
Thierry Brun ◽  
Isabelle Avril ◽  
Valérie M. Schwitzgebel ◽  
...  
Keyword(s):  
Gene Expression ◽  
Transcriptional Activation ◽  
Exocrine Pancreas ◽  
Gene Promoter ◽  
Control Element ◽  
Mobility Shift ◽  
Insulinoma Cell ◽  
Nuclear Extracts ◽  
Endoderm Development ◽  
Gel Mobility Shift

Abstract Gene inactivation studies have shown that members of the Gata family of transcription factors are critical for endoderm development throughout evolution. We show here that Gata-4 and/or Gata-6 are not only expressed in the adult exocrine pancreas but also in glucagonoma and insulinoma cell lines, whereas Gata-5 is restricted to the exocrine pancreas. During pancreas development, Gata-4 is expressed already at embryonic d 10.5 and colocalizes with early glucagon+ cells at embryonic d 12.5. Gata-4 was able to transactivate the glucagon gene both in heterologous BHK-21 (nonislet Syrian baby hamster kidney) and in glucagon-producing InR1G9 cells. Using gel-mobility shift assays, we identified a complex formed with nuclear extracts from InR1G9 cells on the G5 control element (−140 to −169) of the glucagon gene promoter as Gata-4. Mutation of the GATA binding site on G5 abrogated the transcriptional activation mediated by Gata-4 and reduced basal glucagon gene promoter activity in glucagon-producing cells by 55%. Furthermore, Gata-4 acted more than additively with Forkhead box A (hepatic nuclear factor-3) to trans-activate the glucagon gene promoter. We conclude that, besides its role in endoderm differentiation, Gata-4 might be implicated in the regulation of glucagon gene expression in the fetal pancreas and that Gata activity itself may be modulated by interactions with different cofactors.

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