Splice variant of the SND1 transcription factor is a dominant negative of SND1 members and their regulation in Populus trichocarpa

T-lymphocyte stimulation requires activation of several protein kinases, including the major phorbol ester receptor protein kinase C (PKC), ultimately leading to induction of lymphokines, such as interleukin-2 (IL-2). The revelant PKC isoforms which are involved in the activation cascades of nuclear transcription factors involved in IL-2 production have not yet been clearly defined. We have examined the potential role of two representative PKC isoforms in the induction of the IL-2 gene, i.e., PKC-alpha and PKC-theta, the latter being expressed predominantly in hematopoietic cell lines, particularly T cells. Similar to that of PKC-alpha, PKC-theta overexpression in murine EL4 thymoma cells caused a significant increase in phorbol 12-myristate 13-acetate (PMA)-induced transcriptional activation of full-length IL-2-chloramphenicol acetyltransferase (CAT) and NF-AT-CAT but not of NF-IL2A-CAT or NF-kappaB promoter-CAT reporter gene constructs. Importantly, the critical AP-1 enhancer element was differentially modulated by these two distinct PKC isoenzymes, since only PKC-theta but not PKC-alpha overexpression resulted in an approximately 2.8-fold increase in AP-1-collagenase promoter CAT expression in comparison with the vector control. Deletion of the AP-1 enhancer site in the collagenase promoter rendered it unresponsive to PKC-theta. Expression of a constitutively active mutant PKC-theta A148E (but not PKC-alpha A25E) was sufficient to induce activation of AP-1 transcription factor complex in the absence of PMA stimulation. Conversely, a catalytically inactive PKC-theta K409R (but not PKC-alpha K368R) mutant abrogated endogenous PMA-mediated activation of AP-1 transcriptional complex. Dominant negative mutant Ha-RasS17N completely inhibited the PKC-O A148E-induced signal, PKC-O. Expression of a constitutively active mutant PKC-O A148E (but not PKC-alpha A25E) was sufficient to induce activation of AP-1 transcription factor complex in the absence of PMA stimulation. Conversely, a catalytically inactive PKC-O K409R (but not PKC-alpha K368R) mutant abrogated endogenous PMA-mediated activation of AP-1 transcriptional complex. Dominant negative mutant Ha-enRasS17N completely inhibited in the PKC-O A148E-induced signal, identifying PKC-theta as a specific constituent upstream of or parallel to Ras in the signaling cascade leading to AP transcriptional activation.

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CHOP Enhancement of Gene Transcription by Interactions with Jun/Fos AP-1 Complex Proteins

Molecular and Cellular Biology ◽

10.1128/mcb.19.11.7589 ◽

1999 ◽

Vol 19 (11) ◽

pp. 7589-7599 ◽

Cited By ~ 95

Author(s):

Mariano Ubeda ◽

Mario Vallejo ◽

Joel F. Habener

Keyword(s):

Transcription Factor ◽

Gene Transcription ◽

Stress Responses ◽

Leucine Zipper ◽

Target Genes ◽

Cellular Stress ◽

Dominant Negative ◽

Dimerization Domain ◽

Mobility Shift

ABSTRACT The transcription factor CHOP (C/EBP homologous protein 10) is a bZIP protein induced by a variety of stimuli that evoke cellular stress responses and has been shown to arrest cell growth and to promote programmed cell death. CHOP cannot form homodimers but forms stable heterodimers with the C/EBP family of activating transcription factors. Although initially characterized as a dominant negative inhibitor of C/EBPs in the activation of gene transcription, CHOP-C/EBP can activate certain target genes. Here we show that CHOP interacts with members of the immediate-early response, growth-promoting AP-1 transcription factor family, JunD, c-Jun, and c-Fos, to activate promoter elements in the somatostatin, JunD, and collagenase genes. The leucine zipper dimerization domain is required for interactions with AP-1 proteins and transactivation of transcription. Analyses by electrophoretic mobility shift assays and by an in vivo mammalian two-hybrid system for protein-protein interactions indicate that CHOP interacts with AP-1 proteins inside cells and suggest that it is recruited to the AP-1 complex by a tethering mechanism rather than by direct binding of DNA. Thus, CHOP not only is a negative or a positive regulator of C/EBP target genes but also, when tethered to AP-1 factors, can activate AP-1 target genes. These findings establish the existence of a new mechanism by which CHOP regulates gene expression when cells are exposed to cellular stress.

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P273 A case of agammaglobulinemia attributed to heterozygous, dominant-negative mutation in transcription factor E47

Annals of Allergy Asthma & Immunology ◽

10.1016/j.anai.2017.08.189 ◽

2017 ◽

Vol 119 (5) ◽

pp. S69

Author(s):

E. Feuille ◽

B. Boisson ◽

Y. Itan ◽

J. Casanova ◽

C. Cunningham-Rundles

Keyword(s):

Transcription Factor ◽

Dominant Negative ◽

Dominant Negative Mutation

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Headless splice variant acting as dominant negative calcitonin receptor

Biochemical and Biophysical Research Communications ◽

10.1016/j.bbrc.2007.08.107 ◽

2007 ◽

Vol 362 (4) ◽

pp. 1037-1043 ◽

Cited By ~ 14

Author(s):

Kakon Nag ◽

Naznin Sultana ◽

Akira Kato ◽

Shigehisa Hirose

Keyword(s):

Splice Variant ◽

Dominant Negative ◽

Calcitonin Receptor

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The hSkn-1a POU transcription factor enhances epidermal stratification by promoting keratinocyte proliferation

Journal of Cell Science ◽

10.1242/jcs.114.10.1913 ◽

2001 ◽

Vol 114 (10) ◽

pp. 1913-1923 ◽

Cited By ~ 1

Author(s):

J. Hildesheim ◽

U. Kuhn ◽

C.L. Yee ◽

R.A. Foster ◽

K.B. Yancey ◽

...

Keyword(s):

Transcription Factor ◽

Human Keratinocytes ◽

Dominant Negative ◽

Keratinocyte Differentiation ◽

Transactivation Domain ◽

Hacat Keratinocytes ◽

Primary Human Keratinocytes ◽

Keratinocyte Proliferation ◽

Proliferation And Differentiation ◽

Epidermal Homeostasis

Skn-1a is a POU transcription factor that is primarily expressed in the epidermis and is known to modulate the expression of several genes associated with keratinocyte differentiation. However, the formation of a stratified epidermis requires a carefully controlled balance between keratinocyte proliferation and differentiation, and a role for Skn-1a in this process has not been previously demonstrated. Here, our results show, surprisingly, that human Skn-1a contributes to epidermal stratification by primarily promoting keratinocyte proliferation and secondarily by enhancing the subsequent keratinocyte differentiation. In organotypic raft cultures of both primary human keratinocytes and immortalized HaCaT keratinocytes, human Skn-1a expression is associated with increased keratinocyte proliferation and re-epithelialization of the dermal substrates, resulting in increased numbers of keratinocytes available for the differentiation process. In these same raft cultures, human Skn-1a expression enhances the phenotypic changes of keratinocyte differentiation and the upregulated expression of keratinocyte differentiation genes. Conversely, expression of a dominant negative human Skn-1a transcription factor lacking the C-terminal transactivation domain blocks keratinocytes from proliferating and stratifying. Keratinocyte stratification is dependent on a precise balance between keratinocyte proliferation and differentiation, and our results suggest that human Skn-1a has an important role in maintaining epidermal homeostasis by promoting keratinocyte proliferation.

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Abstract 5278: The Sonic Hedgehog Transcription Factor Gli3 Modulates Ischemia-induced Angiogenesis

Circulation ◽

10.1161/circ.118.suppl_18.s_518-c ◽

2008 ◽

Vol 118 (suppl_18) ◽

Author(s):

Marie-Ange Renault ◽

Jerome Roncalli ◽

Joern Tongers ◽

Sol Misener ◽

Tina Thorne ◽

...

Keyword(s):

Transcription Factor ◽

Limb Ischemia ◽

Capillary Density ◽

Left Ventricular ◽

Dominant Negative ◽

Tube Length ◽

Reduced Ejection Fraction ◽

Border Zones

Gli transcription factors are mediators of hedgehog signaling and have been shown to be critical in several steps during development. We have shown that the Hedgehog pathway is reactivated in the adult cardiovascular system under ischemic conditions, however the specific role of Gli3 has not been elucidated. Adenoviral mediated overexpression of Gli3 promotes HUVEC migration (250±58% of control, p<0.001) while down regulation of Gli3 via siRNA delayed tube formation on Matrigel (total tube length after 8 hours 6.86 vs. 70.76 control), suggesting a possible role of Gli3 in angiogenesis. We next investigated the role of Gli3 in angiogenesis using Gli3 +/− (Gli3 +/XtJ ) mice, a well established model of reduced Gli3 expression. VEGF-induced corneal angiogenesis was impaired in Gli3 +/− mice compared to WT. The role of Gli3 in angiogenesis was then confirmed in two ischemia models. Hind-limb ischemia (HLI) was induced by resection of the left femoral artery. Capillary density was reduced by a mean of 48.40±12.08% in Gli3 +/− mice vs. WT 7, 14 and 28 days. Myocardial infarction (MI) was induced by ligation of the LAD. 28 days after MI, left ventricular function assessed by echo and histological analysis revealed that Gli3 +/− mice exhibit reduced ejection fraction (27.92±4.49% versus 37.56±7.02% for the WT, p=0.004), increased fibrosis area (33.65±9.73% versus 19.81±5.40% for the WT, p=0.007) and a decrease capillary density in the ischemic and border zones. These data indicate that Gli3 deficiency leads to impaired angiogenesis in both ischemic and non ischemic conditions. Moreover, the impairment in ischemia induced neovascularization is associated with more severe impairment of cardiac function after MI. The mechanism of Gli3’s effects was then investigated in vitro . Promoter reporter assays revealed that Gli3 overexpression inhibits Gli-dependent transcription, while Western analysis show increased Akt phosphorylation, activation of the ERK1/2 and increased c-Fos expression. Using a dominant negative Akt expressing virus and a MEK1/2 inhibitor, we show that Gli3 induced-EC migration is dependent on Akt and ERK1/2. These studies provide the first evidence that the Gli3 transcription factor regulates angiogenesis and EC phenotype.

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Treatment of cultured myotubes with the proteasome inhibitor β-lactone increases the expression of the transcription factor C/EBPβ

AJP Cell Physiology ◽

10.1152/ajpcell.00282.2006 ◽

2007 ◽

Vol 292 (1) ◽

pp. C216-C226 ◽

Cited By ~ 6

Author(s):

Wei Wei ◽

Hongmei Yang ◽

Michael Menconi ◽

Peirang Cao ◽

Chester E. Chamberlain ◽

...

Keyword(s):

Skeletal Muscle ◽

Transcription Factor ◽

Dna Binding ◽

Proteasome Inhibitor ◽

Binding Activity ◽

Dominant Negative ◽

Dna Binding Activity ◽

Cultured Myotubes ◽

Nuclear Levels ◽

Factor C

The role of the proteasome in the regulation of cellular levels of the transcription factor CCAAT/enhancer-binding protein β (C/EBPβ) is poorly understood. We tested the hypothesis that C/EBPβ levels in cultured myotubes are regulated, at least in part, by proteasome activity. Treatment of cultured L6 myotubes, a rat skeletal muscle cell line, with the specific proteasome inhibitor β-lactone resulted in increased nuclear levels of C/EBPβ as determined by Western blotting and immunofluorescent detection. This effect of β-lactone reflected inhibited degradation of C/EBPβ. Surprisingly, the increased C/EBPβ levels in β-lactone-treated myotubes did not result in increased DNA-binding activity. In additional experiments, treatment of the myotubes with β-lactone resulted in increased nuclear levels of growth arrest DNA damage/C/EBP homologous protein (Gadd153/CHOP), a dominant-negative member of the C/EBP family that can form heterodimers with other members of the C/EBP family and block DNA binding. Coimmunoprecipitation and immunofluorescent detection provided evidence that C/EBPβ and Gadd153/CHOP interacted and colocalized in the nuclei of the β-lactone-treated myotubes. When Gadd153/CHOP expression was downregulated by transfection of myotubes with siRNA targeting Gadd153/CHOP, C/EBPβ DNA-binding activity was restored in β-lactone-treated myotubes. The results suggest that C/EBPβ is degraded by a proteasome-dependent mechanism in skeletal muscle cells and that Gadd153/CHOP can interact with C/EBPβ and block its DNA-binding activity. The observations are important because they increase the understanding of the complex regulation of the expression and activity of C/EBPβ in skeletal muscle.

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