1
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Regulatory roles of Oct proteins in the mammary gland. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2016; 1859:812-9. [PMID: 27044595 DOI: 10.1016/j.bbagrm.2016.03.015] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/15/2016] [Revised: 03/07/2016] [Accepted: 03/24/2016] [Indexed: 11/21/2022]
Abstract
The expression of Oct-1 and -2 and their binding to the octamer motif in the mammary gland are developmentally and hormonally regulated, consistent with the expression of milk proteins. Both of these transcription factors constitutively bind to the proximal promoter of the milk protein gene β-casein and might be involved in the inhibition or activation of promoter activity via interactions with other transcription factors or cofactors at different developmental stages. In particular, the lactogenic hormone prolactin and glucocorticoids induce Oct-1 and Oct-2 binding and interaction with both the signal transducer and activator of transcription 5 (STAT5) and the glucocorticoid receptor on the β-casein promoter to activate β-casein expression. In addition, increasing evidence has shown the involvement of another Oct factor, Oct-3/4, in mammary tumorigenesis, making Oct-3/4 an emerging prognostic marker of breast cancer and a molecular target for the gene-directed therapeutic intervention, prevention and treatment of breast cancer. This article is part of a Special Issue entitled: The Oct Transcription Factor Family, edited by Dr. Dean Tantin.
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2
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Qian X, Zhao FQ. Collaborative interaction of Oct-2 with Oct-1 in transactivation of lactogenic hormones-induced β-casein gene expression in mammary epithelial cells. Gen Comp Endocrinol 2014; 204:185-94. [PMID: 24861805 DOI: 10.1016/j.ygcen.2014.05.021] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/03/2014] [Revised: 05/08/2014] [Accepted: 05/10/2014] [Indexed: 11/27/2022]
Abstract
Octamer-binding transcription factor-1 (Oct-1) is found to mediate lactogenic hormones (prolactin and glucocorticoids, HP)-induced β-casein gene expression in mammary alveolar secretory epithelial cells (MECs). The mammary gland also expresses Oct-2 isoform. In this study, we show that Oct-2 is also involved in HP-induced β-casein expression. Oct-2 endogenously binds to the β-casein promoter in MECs, and HP induce Oct-2 binding activity via mechanisms other than increasing Oct-2 expression or inducing Oct-2 translocation to the nucleus. Oct-2 transactivates HP-induced β-casein gene expression and this function is exchangeable with Oct-1. In MECs, Oct-2 is found to physically interact with Oct-1 regardless of HP treatment. However, HP induce physical interactions of Oct-2 with both signal transducer and activator of transcription 5 (STAT5) and glucocorticoid receptor (GR). These results provided biochemical evidence that Oct-2 may form a heteromer with Oct-1 in induction of β-casein gene expression by HP in MECs.
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Affiliation(s)
- Xi Qian
- Laboratory of Lactation and Metabolic Physiology, Department of Animal Science, University of Vermont, Burlington, VT 05405, USA
| | - Feng-Qi Zhao
- Laboratory of Lactation and Metabolic Physiology, Department of Animal Science, University of Vermont, Burlington, VT 05405, USA.
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3
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Patel AK, Singh M, Suryanarayana VVS. Buffalo alpha S1-casein gene 5'-flanking region and its interspecies comparison. J Appl Genet 2013; 55:75-87. [PMID: 24142689 DOI: 10.1007/s13353-013-0176-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2013] [Revised: 09/04/2013] [Accepted: 09/19/2013] [Indexed: 11/28/2022]
Abstract
The expression of milk protein genes is tightly regulated in a spatio-temporal manner through the combinatorial interaction of lactogenic hormones and a set of transcription factors mediating developmental and tissue-specific gene expression. The recruitment of a unique set of transcription factors is determined by the cis-regulatory motifs present in the gene promoter region. Here, we report the isolation, sequencing, structural analysis and interspecies comparison of the 5'cis-regulatory region of the buffalo alpha S1 (αS1)-casein gene. The proximal promoter region of the buffalo αS1-casein gene harbored the insertion of a 72-bp fragment of long interspersed nuclear element of the L1_BT retrotransposon family. Among the core and vertebrate-specific promoter elements, the motifs for the binding of Brn POU domain factors (BRNF), Lim homeodomain factors (LHXF), NK6 homeobox transcription factors (NKX6), nuclear factor kappa B/c-rel (NFKB), AT-rich interactive domain factor (ARID), Brn POU domain factor 5 (BRN5), pancreatic and intestinal homeodomain transcription factor (PDX1), Distal-less homeodomain transcription factors (DLXF), T-cell factor/lymphoid enhancer-binding factor-1 (LEFF) and GHF-1 pituitary-specific POU domain transcription factor (PIT1) were over-represented in the αS1-casein gene regulatory region (Z score >4.0). The Multiple EM for Motif elicitation predicted three motifs which consisted of the sequences known to bind mammary gland factor/signal transducer and activator of transcription 5 (MGF/STAT5), estrogen receptor-related alpha (ERα), steroidogenic factor 1 (SF1) and glucocorticoid receptor (GR), indicating their potential role in the mammary gland-specific gene expression. The interspecies comparison of the proximal promoter region revealed conserved sequences for TATA boxes and MGF/STAT5 in all species, whereas activator protein 1 (AP1), pregnancy-specific mammary nuclear factor (PMF), CCAAT/enhancer binding protein (C/EBP), double-stranded and single-stranded DNA-binding protein 1 (DS1 and SS), ying and yang factor 1 (YY1), and GR half-sites were among ruminants. The functional significance of the L1_BT retrotransposon insertion on the buffalo αS1-casein gene expression needs to be experimentally validated.
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Affiliation(s)
- Amrutlal K Patel
- Department of Animal Biotechnology, College of Veterinary Science and Animal Husbandry, Anand Agricultural University, Anand, India
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4
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Qian X, Zhao FQ. Interactions of the ubiquitous octamer-binding transcription factor-1 with both the signal transducer and activator of transcription 5 and the glucocorticoid receptor mediate prolactin and glucocorticoid-induced β-casein gene expression in mammary epithelial cells. Int J Biochem Cell Biol 2013; 45:724-35. [PMID: 23313770 DOI: 10.1016/j.biocel.2013.01.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2012] [Revised: 11/27/2012] [Accepted: 01/04/2013] [Indexed: 11/30/2022]
Abstract
Regulation of milk protein gene expression by lactogenic hormones (prolactin and glucocorticoids) provides an attractive model for studying the mechanisms by which protein and steroid hormones synergistically regulate gene expression. β-Casein is one of the major milk proteins and its expression in mammary epithelial cells is stimulated by lactogenic hormones. The signal transducer and activator of transcription 5 and glucocorticoid receptor are essential downstream mediators of prolactin and glucocorticoid signaling, respectively. Previous studies have shown that mutating the octamer-binding site of the β-casein gene proximal promoter dramatically reduces the hormonal induction of the promoter activity. However, little is known about the underlying molecular mechanisms. In this report, we show that lactogenic hormones rapidly induce the binding of octamer-binding transcription factor-1 to the β-casein promoter and this induction is not mediated by either increasing the expression of octamer-binding transcription factor-1 or inducing its translocation to the nucleus. Rather, lactogenic hormones induce physical interactions between the octamer-binding transcription factor-1, signal transducer and activator of transcription 5, and glucocorticoid receptor to form a ternary complex, and these interactions enhance or stabilize the binding of these transcription factors to the promoter. Abolishing these interactions significantly reduces the hormonal induction of β-casein gene transcription. Thus, our study indicates that octamer-binding transcription factor-1 may serve as a master regulator that facilitates the DNA binding of both signal transducer and activator of transcription 5 and glucocorticoid receptor in hormone-induced β-casein expression, and defines a novel mechanism of regulation of tissue-specific gene expression by the ubiquitous octamer-binding transcription factor-1.
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Affiliation(s)
- Xi Qian
- Laboratory of Lactation and Metabolic Physiology, Department of Animal Science, University of Vermont, Burlington, VT 05405, USA
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5
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Talhouk RS, Khalil AA, Bajjani R, Rahme GJ, El-Sabban ME. Gap junctions mediate STAT5-independent β-casein expression in CID-9 mammary epithelial cells. ACTA ACUST UNITED AC 2011; 18:104-16. [DOI: 10.3109/15419061.2011.639468] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Affiliation(s)
- Rabih S. Talhouk
- Department of Biology, American University of Beirut, Beirut, Lebanon
| | - Antoine A. Khalil
- Department of Biology, American University of Beirut, Beirut, Lebanon
| | - Rachid Bajjani
- Department of Biology, American University of Beirut, Beirut, Lebanon
| | - Gilbert J. Rahme
- Department of Biology, American University of Beirut, Beirut, Lebanon
| | - Marwan E. El-Sabban
- Department of Human Morphology, American University of Beirut, Beirut, Lebanon
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6
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Dong B, Huang C, Li D, Zhao FQ. Oct-1 functions as a transactivator in the hormonal induction of beta-casein gene expression. Mol Cell Biochem 2009; 328:93-9. [PMID: 19266165 DOI: 10.1007/s11010-009-0078-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2009] [Accepted: 02/24/2009] [Indexed: 11/24/2022]
Abstract
The ubiquitous transcription factor Oct-1 is involved in the hormonal regulation of the transcription of the major milk protein beta-casein through an interaction with the prolactin receptor, the STAT-5, and the glucocorticoid receptor (GR). In this study, this interaction was further demonstrated using Oct-1-deficient cells. In addition, Oct-1 mRNA expression is shown to increase during pregnancy and reach the highest levels during early lactation in mouse mammary gland. In reconstituted COS-7 cells, the endogenous Oct-1 binding activity rapidly increased within 5 min upon the lactogenic hormone treatment, indicating potential post-transcriptional/translational modification of Oct-1 by prolactin and glucocorticoids. Furthermore, STAT-5B was as effective as STAT-5A in the interaction with Oct-1 during hormonal induction, and a GR mutant, which carries mutations at multiple potential phosphorylation sites, functioned similarly to the wild-type GR, indicating that these phosphorylation sites may not be involved in the interaction of GR with Oct-1 on the beta-casein gene promoter.
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Affiliation(s)
- Bing Dong
- Department of Animal Science, University of Vermont, Burlington, 05405, USA
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7
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Lee P, Chung HK, Lee HG, Lee HC, Woo JS, Lee S, Jo SJ, Chang WK, Lee HT, Kwon M, Park JK. Cloning and characterization of 5'-untranslated region of porcine beta casein gene (CSN2). Domest Anim Endocrinol 2008; 35:245-53. [PMID: 18583090 DOI: 10.1016/j.domaniend.2008.04.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/07/2008] [Revised: 04/23/2008] [Accepted: 04/24/2008] [Indexed: 10/22/2022]
Abstract
beta-Casein (CSN2) is a major milk protein in most mammals. The CSN2 gene is generally induced by lactogenic hormones bound to its promoter. The expression of this gene can be enhanced by signal transducers and activators of transcription (STAT) and glucocorticoid receptor (GR). Here, we analyzed the promoter and intron 1 regions of the porcine CSN2 gene. The porcine CSN2 promoter and intron 1 regions (-3098bp to +2446bp) were cloned into the pGL3-Basic vector containing the luciferase reporter gene (pCSN2-PEI). Lactogenic signals induced the transcription of porcine CSN2. By using AG490, a Janus kinase (JAK) inhibitor, we demonstrated that STAT5 positively regulates the transcription of porcine CSN2. Further, seven STAT mutants were generated by site-directed mutagenesis. By performing electrophoretic mobility shift assays (EMSAs), we located a critical element for pCSN2-PEI transcription bound to STAT5 in the -102bp to -84bp region. The construct containing only the promoter region (pCSN2-P), however, did not exert any promotive effects on transcription in two cell types-a mouse mammary epithelial cell line (HC11) and porcine mammary gland epithelial cells (PMECs). Thus, the construct containing intron 1 of porcine CSN2 exerts an elevating effect on transcription. We suggest that the transcription of porcine CSN2 is regulated by lactogenic signals via the STAT5 site (-102bp to -84bp) and intron 1.
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Affiliation(s)
- Poongyeon Lee
- Animal Biotechnology Division, National Institute of Animal Science, RDA, Suwon, Republic of Korea
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8
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Dong B, Zhao FQ. Involvement of the ubiquitous Oct-1 transcription factor in hormonal induction of beta-casein gene expression. Biochem J 2007; 401:57-64. [PMID: 16965262 PMCID: PMC1698677 DOI: 10.1042/bj20060570] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Transcription of the milk protein beta-casein gene is induced by the lactogenic hormones Prl (prolactin) and glucocorticoids. Multiple transcription factors involved in this induction have been identified, including the STAT5 (signal transducer and activator of transcription 5) and the GR (glucocorticoid receptor). Our previous studies have identified a binding site for the ubiquitous Oct-1 (octamer-binding transcription factor 1) protein in the lactogenic hormonal regulatory region of the mouse beta-casein promoter. In the present study, we report that Oct-1 is indeed expressed and binds to the beta-casein promoter in mammary epithelial cells. Oct-1 activates hormonally induced beta-casein promoter activity in a dose-dependent manner. Hormonal induction of promoter activity was decreased not only by mutating the Oct-1-binding site from ATTAGCAT to GCTAGCAT, which abolishes Oct-1 binding (50% decrease, P<0.01), but also by changing the site to the consensus Oct-1-binding motif ATTTGCAT (40% decrease, P<0.01). Reversing the Oct-1-binding site reduced hormonal induction by 70% (P<0.01), showing that orientation of Oct-1 binding is also critical in hormonal action. In transient transfection experiments, Oct-1 collaboratively transactivated the beta-casein gene promoter with STAT5 and/or GR in the presence of Prl receptor in cells treated with the lactogenic hormones. The C-terminus of Oct-1 was not essential to its function. The results of the present study provide biochemical evidence that the ubiquitous Oct-1 transcription factor may be involved in hormonally regulated, tissue-specific beta-casein gene expression.
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Affiliation(s)
- Bing Dong
- Lactation and Mammary Gland Biology Group, Department of Animal Science, University of Vermont, Burlington, VT 05405, U.S.A
| | - Feng-Qi Zhao
- Lactation and Mammary Gland Biology Group, Department of Animal Science, University of Vermont, Burlington, VT 05405, U.S.A
- To whom correspondence should be addressed, at 219 Terrill, 570 Main Street, Burlington, VT 05405, U.S.A. (email )
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9
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Zhang H, Singh RR, Talukder AH, Kumar R. Metastatic tumor antigen 3 is a direct corepressor of the Wnt4 pathway. Genes Dev 2006; 20:2943-8. [PMID: 17050676 PMCID: PMC1620027 DOI: 10.1101/gad.1461706] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Here we show that expression of MTA3 inhibits ductal branching in virgin and pregnant murine transgenic mammary glands. MTA3 also suppresses the Wnt4 pathway and, thus, these findings parallel phenotypic changes in Wnt4-null mice. MTA3 represses Wnt4 transcription and Wnt4 secretion, inhibiting Wnt-target genes in mammary epithelial cells. Accordingly, knockdown of endogenous MTA3 stimulates Wnt4 expression and Wnt cellular targets. The MTA3-NuRD (nucleosome remodeling and deacetylase) complex physically interacts with the Wnt4 chromatin in an HDAC-dependent manner, leading to suppression of the Wnt4 gene and Wnt4-dependent morphogenesis. These findings identify MTA3 as an upstream physiologic repressor of Wnt4 in mammary epithelial cells.
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Affiliation(s)
- Hao Zhang
- Molecular and Cellular Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
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10
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Abstract
The transcription factor Runx2 is essential for the formation of the skeleton. It has therefore primarily been considered as a specific regulator of bone genes. However, mice containing a LacZ insertion at the Runx2 locus also revealed expression in the nascent mammary epithelium. Reports of Runx2 expression in breast cancer cell lines, combined with the fact that breast cancers preferentially metastasise to bone, have also hinted at a potential role for Runx2 in the formation of bone metastasese. These initial observations have prompted further analysis of Runx2 function in mammary epithelial cells and recent findings have demonstrated that Runx2 does indeed contribute to the ability of metastatic breast cancer cell lines to form osteolytic bone lesions. In addition, evidence is accumulating that Runx2 has a role in the regulation of normal mammary gland gene expression and recent data demonstrate that it regulates transcription of the mammary gland-specific gene, beta-casein. In this article I discuss recent advances that link Runx2 with normal mammary epithelial cell function and the development of bone metastasese in breast cancer.
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Affiliation(s)
- Paul Shore
- Faculty of Life Sciences, University of Manchester, Michael Smith Building, Oxford Road, Manchester M13 9PT, United Kingdom.
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11
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Inman CK, Li N, Shore P. Oct-1 counteracts autoinhibition of Runx2 DNA binding to form a novel Runx2/Oct-1 complex on the promoter of the mammary gland-specific gene beta-casein. Mol Cell Biol 2005; 25:3182-93. [PMID: 15798204 PMCID: PMC1069618 DOI: 10.1128/mcb.25.8.3182-3193.2005] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
The transcription factor Runx2 is essential for the expression of a number of bone-specific genes and is primarily considered a master regulator of bone development. Runx2 is also expressed in mammary epithelial cells, but its role in the mammary gland has not been established. Here we show that Runx2 forms a novel complex with the ubiquitous transcription factor Oct-1 to regulate the expression of the mammary gland-specific gene beta-casein. The Runx2/Oct-1 complex forms on a Runx/octamer element which is highly conserved in casein promoters. Chromatin immunoprecipitation, RNA interference, promoter mutagenesis, and transient expression analyses were used to demonstrate that the Runx2/Oct-1 complex contributes to the transcriptional regulation of the beta-casein gene. Analysis of the complex revealed autoinhibitory domains for DNA binding in both the N-terminal and the C-terminal regions of Runx2. Oct-1 stimulates the recruitment of Runx2 to the beta-casein promoter by interacting with the C-terminal region of Runx2, suggesting that Oct-1 stimulates Runx2 recruitment by relieving the autoinhibition of Runx2 DNA binding. These findings demonstrate that Runx2 collaborates with Oct-1 and contributes to the expression of a mammary gland-specific gene.
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Affiliation(s)
- Claire K Inman
- Faculty of Life Sciences, University of Manchester, Michael Smith Building, Oxford Rd., Manchester M13 9PT, United Kingdom
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12
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Zhao FQ, Adachi K, Oka T. Involvement of Oct-1 in transcriptional regulation of beta-casein gene expression in mouse mammary gland. BIOCHIMICA ET BIOPHYSICA ACTA 2002; 1577:27-37. [PMID: 12151092 DOI: 10.1016/s0167-4781(02)00402-5] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Mouse beta-casein gene promoter contains a region termed block C which is crucial for its gene transcription induced by lactogenic hormones. Nuclear extracts from mouse mammary glands contain at least two binding complexes (DS1 and DS2) which specifically bind to double-stranded block C region DNA. The binding sequence of these complexes was identified to be 5'-AAATTAGCATGT-3' which contains a sequence element related to the consensus octamer motif's complement ATTTGCAT. In the present study, we demonstrate that this sequence element indeed is the binding site for octamer-binding transcription factors (Octs) and Octs represent the double-stranded DNA binding proteins specifically binding to the block C region. Formation of the specific double-stranded binding complexes can be completely blocked by Oct binding motif oligonucleotides and anti-rOct-1 antiserum. We also show that Oct-1B represents at least partial, if not all, double-stranded binding protein, DS1, in mammary nuclear extract. Oct-1B may function as a transcriptional activator on casein gene promoter. The Oct binding activity to beta-casein gene promoter in the mammary gland is affected under influence of hormones both in vitro and in vivo. The DS1 binding activity can be induced by the combination of lactogenic hormones insulin, hydrocortisone and prolactin in organ culture of virgin mouse mammary gland. The binding activity in vivo can be induced by injection of progesterone or its combination with estradiol in virgin mice.
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Affiliation(s)
- Feng-Qi Zhao
- Laboratory of Genetics and Physiology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA
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13
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Saito H, Morita Y, Fujimoto M, Narazaki M, Naka T, Kishimoto T. IFN regulatory factor-1-mediated transcriptional activation of mouse STAT-induced STAT inhibitor-1 gene promoter by IFN-gamma. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2000; 164:5833-43. [PMID: 10820262 DOI: 10.4049/jimmunol.164.11.5833] [Citation(s) in RCA: 75] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
STAT-induced STAT inhibitor-1 (SSI-1), also referred to as suppressor of cytokine signaling-1 and JAK-binding protein, is a member of a new family, the members of which are negative regulators of cytokine signals. SSI-1 is induced by various cytokines; however, the transcriptional mechanism of the SSI-1 gene is not fully understood. Here, we showed that transcription of the mouse SSI-1 gene was initiated from six adjoining sites accompanying three GC boxes and a single GC box-like element near them, but not from the TATA box or an initiator sequence. We also showed that IFN-gamma induced SSI-1 mRNA more strongly than IL-6 in NIH-3T3 fibroblasts and that this IFN-gamma effect was mediated by Stat1. To determine the signal pathway downstream of Stat1, transcriptional activities of several mutant promoters were examined. The region mediating stimulatory effect of IFN-gamma to the gene transcription was localized to the -88/-60 region containing three tandem GAAA units, named variant IFN-gamma-responsive element (VIRE), while four IFN-gamma activation site (GAS)-like elements located far upstream were not related to the IFN-gamma response. Gel-shift assays revealed that IFN-gamma induced IFN regulatory factor-1 (IRF-1) binding to VIRE, but not that of IRF-2 or three components of ISGF3. Furthermore, forced expression of IRF-1 mimicked and that of IRF-2 inhibited the stimulatory effect of IFN-gamma on SSI-1 gene transcription. Finally, mouse embryonal fibroblasts lacking IRF-1 showed impaired SSI-1 mRNA induction by IFN-gamma. These results demonstrated that IRF-1, which is induced by activation of Stat1, mediated transcriptional activation of the SSI-1 gene by IFN-gamma via VIRE.
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Affiliation(s)
- H Saito
- Department of Molecular Medicine, Osaka University Medical School, and Osaka University, Suita City, Osaka, Japan.
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14
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Rothman-Denes LB, Dai X, Davydova E, Carter R, Kazmierczak K. Transcriptional regulation by DNA structural transitions and single-stranded DNA-binding proteins. COLD SPRING HARBOR SYMPOSIA ON QUANTITATIVE BIOLOGY 1999; 63:63-73. [PMID: 10384271 DOI: 10.1101/sqb.1998.63.63] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Affiliation(s)
- L B Rothman-Denes
- Department of Molecular Genetics and Cell Biology, University of Chicago, Illinois 60637, USA
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15
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Kelm RJ, Cogan JG, Elder PK, Strauch AR, Getz MJ. Molecular interactions between single-stranded DNA-binding proteins associated with an essential MCAT element in the mouse smooth muscle alpha-actin promoter. J Biol Chem 1999; 274:14238-45. [PMID: 10318844 DOI: 10.1074/jbc.274.20.14238] [Citation(s) in RCA: 77] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Transcriptional activity of the mouse vascular smooth muscle alpha-actin gene in fibroblasts is regulated, in part, by a 30-base pair asymmetric polypurine-polypyrimidine tract containing an essential MCAT enhancer motif. The double-stranded form of this sequence serves as a binding site for a transcription enhancer factor 1-related protein while the separated single strands interact with two distinct DNA binding activities termed VACssBF1 and 2 (Cogan, J. G., Sun, S., Stoflet, E. S., Schmidt, L. J., Getz, M. J., and Strauch, A. R. (1995) J. Biol. Chem. 270, 11310-11321; Sun, S., Stoflet, E. S., Cogan, J. G., Strauch, A. R., and Getz, M. J. (1995) Mol. Cell. Biol. 15, 2429-2936). VACssBF2 has been recently cloned and shown to consist of two closely related proteins, Puralpha and Purbeta (Kelm, R. J., Elder, P. K., Strauch, A. R., and Getz, M. J. (1997) J. Biol. Chem. 272, 26727-26733). In this study, we demonstrate that Puralpha and Purbeta interact with each other via highly specific protein-protein interactions and bind to the purine-rich strand of the MCAT enhancer in the form of both homo- and heteromeric complexes. Moreover, both Pur proteins interact with MSY1, a VACssBF1-like protein cloned by virtue of its affinity for the pyrimidine-rich strand of the enhancer. Interactions between Puralpha, Purbeta, and MSY1 do not require the participation of DNA. Combinatorial interactions between these three single-stranded DNA-binding proteins may be important in regulating activity of the smooth muscle alpha-actin MCAT enhancer in fibroblasts.
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Affiliation(s)
- R J Kelm
- Department of Biochemistry and Molecular Biology, Mayo Clinic/Foundation, Rochester, Minnesota 55905, USA
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16
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Adachi K, Tanaka T, Saito H, Oka T. Hormonal induction of mouse selenocysteine transfer ribonucleic acid (tRNA) gene transcription-activating factor and its functional importance in the selenocysteine tRNA gene transcription in mouse mammary gland. Endocrinology 1999; 140:618-23. [PMID: 9927285 DOI: 10.1210/endo.140.2.6501] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Mouse selenocysteine transfer RNA (tRNA) gene transcription-activating factor (mStaf) is a transcriptional activator that enhances RNA polymerase III-dependent mouse selenocysteine tRNA (tRNA(Sec)) gene transcription. The DNA-binding activity of mStaf in mouse mammary gland undergoes developmental changes, reaching a maximal level during the period of lactation. In this study, we employed an organ culture system to examine the hormonal regulation of mStaf binding and its role in the tRNA(Sec) transcription in the mammary gland. The results showed that mStaf binding in mammary explants was stimulated by treatment with the lactogenic hormones, PRL, insulin, and hydrocortisone and that a specific MEK inhibitor, PD98059, inhibited the hormonal stimulation of mStaf binding. Other kinase inhibitors, such as a Janus kinase inhibitor and a calmodulin kinase inhibitor, had no apparent effect. Northern and Western blot analyses revealed that the level of both mStaf messenger RNA and protein was enhanced by the lactogenic hormones and was reduced by the concomitant treatment with PD98059. The mitogen-activated protein kinase activity in cultured explants was rapidly induced and maintained at high levels by the lactogenic hormones. We also found that the lactogenic hormones increased the amount of tRNA(Sec) in a time-dependent manner, which followed the increase in mStaf binding in cultured mammary explants. These results support the view that mStaf plays a key role in the hormonal stimulation of tRNA(Sec) transcription in the mammary gland.
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Affiliation(s)
- K Adachi
- Laboratory of Molecular and Cellular Biology, National Institutes of Diabetes, Digestive, and Kidney Disease, National Institutes of Health, Bethesda, Maryland 20892, USA
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Adachi K, Saito H, Tanaka T, Oka T. Molecular cloning and characterization of the murine staf cDNA encoding a transcription activating factor for the selenocysteine tRNA gene in mouse mammary gland. J Biol Chem 1998; 273:8598-606. [PMID: 9535833 DOI: 10.1074/jbc.273.15.8598] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
We have isolated and characterized a cDNA encoding a transcription activating factor for the mouse selenocysteine tRNA (tRNAsec) gene from mouse mammary gland. The full-length cDNA, designated m-Staf, has a 1878-base pair open reading frame encoding 626 amino acids. The predicted amino acid sequence of m-Staf is highly homologous to that of Staf, another selenocysteine tRNA gene transcription activating factor of Xenopus laevis. Like Staf, m-Staf contains seven tandemly repeated zinc fingers and four repeated motifs. Gel shift assays indicated that the recombinant m-Staf specifically bound to the activator element region in the mouse tRNAsec gene. Transient co-transfection experiments in Drosophila Schneider cells, which lack endogenous Staf-like binding activity, showed that m-Staf increased the mouse tRNAsec gene transcription about 15-fold, whereas it stimulated Pol II-dependent thymidine kinase promoter only 2-fold. Northern blot analysis detected the presence of a 3.4-kilobase pair m-Staf transcript, which was widely but differentially expressed in various murine tissues. The binding activity of m-Staf in mouse mammary gland was undetectable during virgin and postlactating periods but increased markedly in parallel with the increase of tRNAsec transcript during the periods of pregnancy and lactation, when the gland undergoes growth and development. These results indicate that m-Staf is a transcriptional activator of the mouse tRNAsec gene and that its binding activity in the mammary gland undergoes developmental alterations.
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MESH Headings
- Amino Acid Sequence
- Animals
- Base Sequence
- Cell Line
- Cloning, Molecular
- DNA Polymerase III/biosynthesis
- DNA Polymerase III/genetics
- DNA, Complementary
- DNA-Binding Proteins/biosynthesis
- DNA-Binding Proteins/chemistry
- DNA-Binding Proteins/metabolism
- Drosophila melanogaster
- Female
- Gene Expression Regulation
- Gene Library
- Lactation
- Mammary Glands, Animal/metabolism
- Mice
- Molecular Sequence Data
- Pregnancy
- Promoter Regions, Genetic
- RNA, Transfer, Amino Acid-Specific/biosynthesis
- RNA, Transfer, Amino Acid-Specific/genetics
- Recombinant Proteins/biosynthesis
- Recombinant Proteins/chemistry
- Recombinant Proteins/metabolism
- Sequence Alignment
- Sequence Homology, Amino Acid
- Sequence Homology, Nucleic Acid
- Trans-Activators/biosynthesis
- Trans-Activators/chemistry
- Trans-Activators/metabolism
- Transcriptional Activation
- Transfection
- Xenopus Proteins
- Xenopus laevis
- Zinc Fingers
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Affiliation(s)
- K Adachi
- Laboratory of Molecular and Cellular Biology, NIDDK, National Institutes of Health, Bethesda, Maryland 20892, USA
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Di Matteo G, Salerno M, Guarguaglini G, Di Fiore B, Palitti F, Lavia P. Interactions with single-stranded and double-stranded DNA-binding factors and alternative promoter conformation upon transcriptional activation of the Htf9-a/RanBP1 and Htf9-c genes. J Biol Chem 1998; 273:495-505. [PMID: 9417108 DOI: 10.1074/jbc.273.1.495] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
The murine Htf9-a/RanBP1 and Htf9-c genes are divergently transcribed from a shared TATA-less promoter. Transcription of both genes is initiated on complementary DNA strands and is controlled by cell cycle-dependent mechanisms. The bidirectional promoter harbors a genomic footprint flanking the major transcription start site of both genes. Transient promoter assays showed that the footprinted element is important for transcription of both genes. Protein-binding experiments and antibody assays indicated that members of the retinoid X receptor family interact with the double-stranded site. In addition, distinct factors interact with single DNA strands of the element. Double-stranded binding factors were highly expressed in liver cells, in which neither gene is transcribed, while single-stranded binding proteins were abundant in cycling cells, in which transcription of both genes is efficient. In vivo S1 analysis of the promoter depicted an S1-sensitive organization in cells in which transcription of both genes is active; S1 sensitivity was not detected in conditions of transcriptional repression. Thus, the same element is a target for either retinoid X receptor factors, or for single-stranded binding proteins, and form distinct complexes in different cellular conditions depending on the DNA conformation in the binding site.
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Affiliation(s)
- G Di Matteo
- CNR Centre of Evolutionary Genetics, c/o Department of Genetics and Molecular Biology, University "La Sapienza," Rome 00185, Italy
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Pham VP, Rothman PB, Gottesdiener KM. Binding of trans-acting factors to the double-stranded variant surface glycoprotein (VSG) expression site promoter of Trypanosoma brucei. Mol Biochem Parasitol 1997; 89:11-23. [PMID: 9297697 DOI: 10.1016/s0166-6851(97)00094-7] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Trypanosoma brucei evades its host's immune response by utilizing the system of antigenic variation, whereby the organism sequentially expresses antigenically distinct variant surface glycoproteins (VSGs). Actively expressed VSG genes are found in VSG expression sites (ESs), and transcription of these ESs is directed by a small promoter composed of two essential cis-acting elements, the VSG ES promoter upstream element (VUE) and VSG ES promoter downstream element (VDE). Using electrophoretic mobility shift assays, we have identified double-stranded DNA binding activity in bloodstream-form trypanosome nuclear extracts. This activity, the VEP complex, is specific for the VSG ES promoter, and requires the intact sequences of the VUE and VDE in the appropriate spacing. These requirements of VEP Complex formation parallel the requirements for promoter function, suggesting that the VEP complex may be composed of functionally significant trans-acting factors. Furthermore, the requirement of both elements suggests that the binding of factors to the promoter may be cooperative. However, subtly different binding characteristics were observed when we used nuclear extracts derived from procyclic trypanosomes.
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Affiliation(s)
- V P Pham
- Department of Microbiology, Columbia College of Physicians and Surgeons, New York 10032, USA
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Moriggl R, Berchtold S, Friedrich K, Standke GJ, Kammer W, Heim M, Wissler M, Stöcklin E, Gouilleux F, Groner B. Comparison of the transactivation domains of Stat5 and Stat6 in lymphoid cells and mammary epithelial cells. Mol Cell Biol 1997; 17:3663-78. [PMID: 9199300 PMCID: PMC232218 DOI: 10.1128/mcb.17.7.3663] [Citation(s) in RCA: 101] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Stat (signal transducers and activators of transcription) and Jak (Janus kinases) proteins are central components in the signal transduction events in hematopoietic and epithelial cells. They are rapidly activated by various cytokines, hormones, and growth factors. Upon ligand binding and cytokine receptor dimerization, Stat proteins are phosphorylated on tyrosine residues by Jak kinases. Activated Stat proteins form homo- or heterodimers, translocate to the nucleus, and induce transcription from responsive genes. Stat5 and Stat6 are transcription factors active in mammary epithelial cells and immune cells. Prolactin activates Stat5, and interleukin-4 (IL-4) activates Stat6. Both cytokines are able to stimulate cell proliferation, differentiation, and survival. We investigated the transactivation potential of Stat6 and found that it is not restricted to lymphocytes. IL-4-dependent activation of Stat6 was also observed in HC11 mammary epithelial cells. In these cells, Stat6 activation led to the induction of the beta-casein gene promoter. The induction of this promoter was confirmed in COS7 cells. The glucocorticoid receptor was able to further enhance IL-4-induced gene transcription through the action of Stat6. Deletion analysis of the carboxyl-terminal region of Stat6 and recombination of this region with a heterologous DNA binding domain allowed the delimitation and characterization of the transactivation domain of Stat6. The potencies of the transactivation domains of Stat5, Stat6, and viral protein VP16 were compared. Stat6 had a transactivation domain which was about 10-fold stronger than that of Stat5. In pre-B cells (Ba/F3), the transactivation domain of Stat6 was IL-4 regulated, independently from its DNA binding function.
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Affiliation(s)
- R Moriggl
- Tumor Biology Center, and Dept. of Biology, University of Freiburg, Germany
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