Up-regulation of Na,K-ATPase β1 Transcription by Hyperoxia Is Mediated by SP1/SP3 Binding

Wendt, Christine; Gick, Greg; Sharma, Rati; Zhuang, Yong; Deng, Wenlian; Ingbar, David H.

doi:10.1074/jbc.m004759200

Cited by 26 publications

(19 citation statements)

References 33 publications

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“…Mutation of murine GC/GA elements within the cardiac troponin I promoter produces a four-to fivefold reduction of promoter activity comparable to that seen for the avian cTnT promoter. Putative Sp1 promoter elements have also been shown to be required for optimal activity of cardiac and skeletal ␣-actin, sarco(endo)plasmic Ca 2ϩ -ATPase, and Na ϩ -K ϩ -ATPase ␤ 1 -subunit genes in cultured cells (6,16,24,31,33). These studies do not show direct trans-activation of promoter constructs cotransfected with expressed Sp factors.…”

Section: Sp1 Activates the ϫ268ctnt Promotermentioning

confidence: 68%

Sp3 inhibits Sp1-mediated activation of the cardiac troponin T promoter and is downregulated during pathological cardiac hypertrophy in vivo

Azakie¹,

Fineman²

2006

American Journal of Physiology-Heart and Circulatory Physiology

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Azakie, Anthony, Jeffrey R. Fineman, and Youping He. Sp3 inhibits Sp1-mediated activation of the cardiac troponin T promoter and is downregulated during pathological cardiac hypertrophy in vivo. Am J Physiol Heart Circ Physiol 291: H600 -H611, 2006. First published April 14, 2006; doi:10.1152/ajpheart.01305.2005.-Combinatorial interactions between cis elements and trans-acting factors are required for regulation of cardiac gene expression during normal cardiac development and pathological cardiac hypertrophy. Sp factors bind GC boxes and are implicated in recruitment and assembly of the basal transcriptional complex. In this study, we show that the cardiac troponin T (cTnT) promoter contains a GC box that is necessary for basal and cAMP-mediated activity of cTnT promoter constructs transfected in embryonic cardiomyocytes. Cardiac nuclear proteins bind the cTnT GC box in a sequence-specific fashion and consist of Sp1, Sp2, and Sp3 protein factors. By chromatin immunoprecipitation, Sp1 binds the cTnT promoter "in vivo." Cotransfected Sp1 trans-activates the cTnT promoter in cardiomyocytes in culture. Sp3 represses Sp1-mediated transcriptional activation of the cTnT gene in embryonic cardiomyocytes. Sp3 repression of Sp1-mediated cTnT promoter activation is dose dependent, inferring a mechanism of competitive binding/inhibition. To evaluate the role of Sp factors in cardiac gene expression in vivo, we have established a clinically relevant animal model of pathological cardiac hypertrophy where the fetal cardiac program is activated. In this animal model, cardiac hypertrophy results from increased left-right shunting, volume loading of the left ventricle, and pressure loading of the right ventricle. Sp1 expression is increased in all four hypertrophied cardiac chambers, whereas Sp3 expression is diminished. This observation is consistent with the in vitro activating function of Sp1 and inhibitory effects of Sp3 on activity of cTnT promoter constructs. Sp factor levels are modulated during the hypertrophic cardiac program in vivo. promoter function; transcription factors; cardiac differentiation; cell specification; cardiac muscle hypertrophy THE SP FAMILY OF TRANSCRIPTION factors is characterized by a series of three zinc fingers at the carboxy-terminal end of the protein that are preceded by glutamine-and serine-threoninerich domains (8, 28). Sp proteins bind GC boxes and the related GT/CACC-box motifs and are implicated in the recruitment and assembly of the basal transcriptional complex. GC boxes have been implicated in the regulation of cardiac promoters, but the direct effects of Sp family members on cardiac promoter activity have not been defined.We use the cardiac troponin T (cTnT) gene promoter as a model of cardiac-specific gene expression during myocardial differentiation (3,5,22,27,29). The cTnT promoter is developmentally regulated by numerous promoter motifs and transacting factors, including MCAT or transcription enhancer factor-1 (TEF-1) binding sites, AT-rich/monocyte enhancer factor-2 (MEF-2) bindin...

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Section: Sp1 Activates the ϫ268ctnt Promotermentioning

confidence: 68%

Sp3 inhibits Sp1-mediated activation of the cardiac troponin T promoter and is downregulated during pathological cardiac hypertrophy in vivo

Azakie¹,

Fineman²

2006

American Journal of Physiology-Heart and Circulatory Physiology

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“…Oxidation of cysteine residues, under conditions of oxidative stress, in zinc fingercontaining transcription factors such as Sp1, result in reduced DNA binding and transcriptional activities (64). Although generally oxidant stress results in reduced Sp1 DNA binding and transcriptional activity, there are instances where oxidant stress increased DNA binding and transcriptional activities of Sp1 and Sp3 to increase promoter activity as in the case of hyperoxia regulation of Na,K-ATPase-␤1 (66). Our data indicated that, although TNF-␣ did not inhibit Sp1 DNA binding activity, it inhibited Sp1 activation of TTF-1 promoter, indicating independent regulation of Sp1 DNA binding activity and promoter activation.…”

Section: Discussionmentioning

confidence: 98%

Thyroid transcription factor-1 (TTF-1) gene: identification of ZBP-89, Sp1, and TTF-1 sites in the promoter and regulation by TNF-α in lung epithelial cells

Das

Acharya

Gottipati

et al. 2011

American Journal of Physiology-Lung Cellular and Molecular Phys

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Thyroid transcription factor-1 (TTF-1/Nkx2.1/TITF1) is a homeodomain-containing transcription factor essential for the morphogenesis and differentiation of the lung. In the lung, TTF-1 controls the expression of surfactant proteins that are essential for lung stability and lung host defense. In this study, we identified functionally important transcription factor binding sites in the TTF-1 proximal promoter and studied tumor necrosis factor-α (TNF-α) regulation of TTF-1 expression. TNF-α, a proinflammatory cytokine, has been implicated in the pathogenesis of acute respiratory distress syndrome (ARDS) and inhibits surfactant protein levels. Deletion analysis of TTF-1 5'-flanking DNA indicated that the TTF-1 proximal promoter retained high-level activity. Electrophoretic mobility shift assay, chromatin immunoprecipitation, and mutational analysis experiments identified functional ZBP-89, Sp1, Sp3, and TTF-1 sites in the TTF-1 proximal promoter. TNF-α inhibited TTF-1 protein levels in H441 and primary alveolar type II cells. TNF-α inhibited TTF-1 gene transcription and promoter activity, indicating that transcriptional mechanisms play important roles in the inhibition of TTF-1 levels. TNF-α inhibited TTF-1 but not Sp1 or hepatocyte nuclear factor-3 DNA binding to TTF-1 promoter. Transactivation experiments in A549 cells indicated that TNF-α inhibited TTF-1 promoter activation by exogenous Sp1 and TTF-1 without altering their levels, suggesting inhibition of transcriptional activities of these proteins. TNF-α inhibition of TTF-1 expression was associated with increased threonine, but not serine, phosphorylation of Sp1. Because TTF-1 serves as a positive regulator for surfactant protein gene expression, TNF-α inhibition of TTF-1 expression could have important implications for the reduction of surfactant protein levels in diseases such as ARDS.

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“…Although Sp1 family members often function to maintain basal transcription rates, Sp1 also plays an important role in regulation of transcription under conditions such as oxidative stress (47). Indeed, in two lung epithelial cell lines and in MDCK cells, the increased transcription of the rat ␤ 1 subunit gene in response to hyperoxia is mediated through increased Sp1 binding (48). Similarly, in neonatal rat cardiac myocytes, the increased rat ␤ 1 subunit transcription rate is associated with increased Sp1 binding (49).…”

Section: Fig 8 Involvement Of the Pkc Pathwaymentioning

confidence: 99%

Identification of a Prostaglandin-responsive Element in the Na,K-ATPase β1 Promoter That Is Regulated by cAMP and Ca2+

Matlhagela

Borsick

Rajkhowa

et al. 2005

Journal of Biological Chemistry

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The Na,K-ATPase is a transmembrane protein responsible for maintaining electrochemical gradients across the plasma membrane in all mammalian cells, a process that is subject to regulation at the transcriptional as well as post-transcriptional level. Included among physiologic regulators in the kidney are prostaglandins. Previously, we demonstrated that prostaglandin E 1 (PGE 1 ) increases the activity and expression of the Na,KATPase in Madin-Darby canine kidney cells (Taub, M., Borsick, M., Geisel, J., Matlhagela, K., Rajkhowa, T., and In this work, we present evidence that transcription of the Na,K-ATPase ␤ 1 subunit is stimulated by PGE 1 , an effect that may be mediated through the cAMP and Ca 2؉ pathways. Transient transfection studies using 5-deletion mutants of the human ␤ 1 subunit promoter indicated that region ؊100 to ؊92 containing the sequence AGTCCCTGC (a prostaglandin-responsive element (PGRE)) is required to elicit the stimulatory effects of PGE 1 , 8-bromo-cAMP, phorbol 12-myristate 13-acetate, and okadaic acid. Electrophoretic mobility shift assays indicated that both the cAMP regulatory element-binding protein (CREB) and Sp1 bind to the PGRE present within this region of the ␤ 1 subunit promoter. The involvement of the PGRE and Sp1 sites in regulation by PGE 1 was further confirmed by the increased PGE 1 stimulation that was observed following insertion of the PGRE into a promoter/luciferase construct containing a portion of a heterologous promoter and the fibronectin promoter with four GC boxes. Further evidence suggesting an interaction between Sp1 and CREB was obtained from experiments conducted with pLuc-MCS-␤72-167, which contains region ؊167 to ؊72 in the human ␤ 1 subunit promoter. The PGE 1 stimulation observed in Madin-Darby canine kidney cells transiently transfected with pLuc-MCS-␤72-167 was reduced when the two GC boxes immediately upstream from the PGRE were translocated farther upstream. Also consistent with an interaction between CREB and Sp1 are the results of our immunoprecipitation studies indicating that CREB co-immunoprecipitated with Sp1 when an antibody against CREB, Sp1, or the CREB-binding protein was used.

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Up-regulation of Na,K-ATPase β1 Transcription by Hyperoxia Is Mediated by SP1/SP3 Binding

Cited by 26 publications

References 33 publications

Sp3 inhibits Sp1-mediated activation of the cardiac troponin T promoter and is downregulated during pathological cardiac hypertrophy in vivo

Sp3 inhibits Sp1-mediated activation of the cardiac troponin T promoter and is downregulated during pathological cardiac hypertrophy in vivo

Thyroid transcription factor-1 (TTF-1) gene: identification of ZBP-89, Sp1, and TTF-1 sites in the promoter and regulation by TNF-α in lung epithelial cells

Identification of a Prostaglandin-responsive Element in the Na,K-ATPase β1 Promoter That Is Regulated by cAMP and Ca2+

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