scholarly journals Functional Myc-Max heterodimer is required for activation-induced apoptosis in T cell hybridomas.

1994 ◽  
Vol 180 (6) ◽  
pp. 2413-2418 ◽  
Author(s):  
R P Bissonnette ◽  
A McGahon ◽  
A Mahboubi ◽  
D R Green
Keyword(s):  
T Cell ◽  
Apoptotic Cell ◽  
Tolerance Induction ◽  
Dominant Negative ◽  
Binding Partner ◽  
Dominant Negative Form ◽  
Dominant Negative Activity ◽  
Induced Apoptosis ◽  
Negative Form

T cell hybridomas respond to activation signals by undergoing apoptotic cell death, and this is likely to represent comparable events related to tolerance induction in immature and mature T cells in vivo. Previous studies using antisense oligonucleotides implicated the c-Myc protein in the phenomenon of activation-induced apoptosis. This role for c-Myc in apoptosis is now confirmed in studies using a dominant negative form of its heterodimeric binding partner, Max, which we show here inhibits activation-induced apoptosis. Further, coexpression of a reciprocally mutant Myc protein capable of forming functional heterodimers with the mutant Max can compensate for the dominant negative activity and restore activation-induced apoptosis. These results imply that Myc promotes activation-induced apoptosis by obligatory heterodimerization with Max, and therefore, by regulating gene transcription.

Both Stat3-Activation and Stat3-Independent BCL2 Downregulation Are Important for Interleukin-6–Induced Apoptosis of 1A9-M Cells

Blood ◽  
1999 ◽  
Vol 93 (4) ◽  
pp. 1346-1354 ◽  
Author(s):  
Kenji Oritani ◽  
Yoshiaki Tomiyama ◽  
Paul W. Kincade ◽  
Keisuke Aoyama ◽  
Takafumi Yokota ◽  
...  
Keyword(s):  
Interleukin 6 ◽  
Cell Formation ◽  
Dominant Negative ◽  
Expression Cloning ◽  
M Cells ◽  
Macrophage Differentiation ◽  
Dominant Negative Form ◽  
Induced Apoptosis ◽  
Bcl2 Gene ◽  
Negative Form

Abstract A unique subclone of a bone marrow-derived stromal cell line, BMS2.4, produces soluble factors that inhibit proliferation of several types of hematopoietic cell lines. An understanding of these molecules may be informative about negative regulatory circuits that can potentially limit blood cell formation. We used expression cloning to identify interleukin-6 (IL-6) as one factor that suppressed growth of a pre-B–cell variant line, 1A9-M. Moreover, IL-6 induced macrophage-differentiation and apoptosis of 1A9-M cells. During this process, IL-6 downregulated expression of BCL2 in 1A9-M cells and stimulated BCL-XL expression, but had no effect on p53, Bax, or Bak gene expression. Mechanisms for transduction of IL-6–induced signals were then evaluated in IL-6–stimulated 1A9-M cells. Whereas the signal transducer and activator of transcription 3 (Stat3) was phosphorylated and activated, there was no effect on either Stat1 or Stat5. The importance of BCL2 and Stat3 on IL-6–induced macrophage-differentiation and apoptosis was studied with 1A9-M cells expressing human BCL2 or a dominant-negative form of Stat3, respectively. IL-6–induced apoptosis, but not macrophage-differentiation, was blocked by continuously expressed BCL2. A dominant-negative form of Stat3 inhibited both macrophage-differentiation and apoptosis induced by IL-6. However, diminished Stat3 activity did not prevent IL-6–induced downregulation of the BCL2 gene. Therefore, activation of Stat3 is essential for IL-6–induced macrophage-differentiation and programmed cell death in this model. Whereas overexpression of BCL2 abrogates the apoptotic response, Stat3-independent signals appear to downregulate expression of the BCL2 gene.

FGF suppresses apoptosis and induces differentiation of fibre cells in the mouse lens

Development ◽  
1995 ◽  
Vol 121 (12) ◽  
pp. 4383-4393 ◽  
Author(s):  
R.L. Chow ◽  
G.D. Roux ◽  
M. Roghani ◽  
M.A. Palmer ◽  
D.B. Rifkin ◽  
...  
Keyword(s):  
Growth Factor ◽  
Transgenic Mice ◽  
Dominant Negative ◽  
Fgf Receptor ◽  
Fibre Cell ◽  
Dominant Negative Form ◽  
Lens Fibre ◽  
Mouse Lens ◽  
Negative Form

To determine whether fibroblast growth factor (FGF) has a role in lens development, we have generated transgenic mice expressing a dominant-negative form of the murine FGF receptor-1 (FGFRDN) in the lens. Using the fibre cell-specific alpha A-crystallin promoter to express the FGFRDN, we have asked whether FGF is required for fibre cell differentiation. The transgenic mice display diminished differentiation of fibre cells as indicated by their reduced elongation. In addition, transgenic lenses have an unusual refractile anomaly that morphological and biochemical data show results from the apoptosis of fibre cells in the central region of the lens. These results show that lens fibre cells are dependent on FGF for their survival and differentiation, and demonstrate that growth factor deprivation in vivo can lead to apoptosis.

Abstract 1473: Identification Of A New NRSF-binding Partner, Zfp90, Which Negatively Regulates The Repression Activity Of NRSF, A Critical Transcriptional Regulator Of Cardiac Fetal Gene Program

Circulation ◽  
2008 ◽  
Vol 118 (suppl_18) ◽  
Author(s):  
Masao Murakami ◽  
Koichiro Kuwahara ◽  
Masaki Harada ◽  
Yasuaki Nakagawa ◽  
Satoru Usami ◽  
...  
Keyword(s):  
Molecular Mechanisms ◽  
Dominant Negative ◽  
Assay System ◽  
Negative Regulator ◽  
Binding Partner ◽  
Arrhythmic Death ◽  
Dominant Negative Form ◽  
Cardiac Gene ◽  
Hybrid Screening ◽  
Negative Form

Neuron-restrictive silencer factor, NRSF is a Zn-finger transcription factor that specifically binds to DNA sequence called NRSE to repress the transcription. NRSF is involved in various biological processes, such as neuronal differentiation, carcinogenesis, and cardiac homeostasis. We previously reported that NRSF regulates the transcription of multiple fetal cardiac genes. Cardiac-specific overexpression of a dominant-negative form of NRSF in mice induced reactivation of fetal cardiac gene program, cardiac dysfunction, and sudden arrhythmic death, suggesting NRSF plays important roles in normal cardiac homeostasis. However, the molecular mechanisms or signaling pathways that regulate the activity of NRSF have not been well understood. In an attempt to clarify the regulators of NRSF, we performed yeast two-hybrid screening using NRSF as bait and identified Zfp90 as NRSF-binding protein. NRSF and Zfp90 co-localize in the nuclear, and Zn-finger domain of NRSF specifically interacted with KRAB domain of Zfp90. To monitor the activity of NRSF sensitively, we made NRSF-responsive reporters using NRSE sequence of BNP promoter and established assay system for estimating the NRSF activity. In this assay system, expression of NRSF repressed the reporter activity and co-expression of Zfp90 restored it. Furthermore the expression levels of Zfp90 were elevated in the hearts with cardiomyopathy. These results suggest that Zfp90 functions as a negative regulator of NRSF and contributes to the genetic remodeling during the development of cardiomyopathy..

scholarly journals Myocardial Expression of a Dominant-Negative Form of Daxx Decreases Infarct Size and Attenuates Apoptosis in an In Vivo Mouse Model of Ischemia/Reperfusion Injury

Circulation ◽  
2007 ◽  
Vol 116 (23) ◽  
pp. 2709-2717 ◽  
Author(s):  
François Roubille ◽  
Stéphane Combes ◽  
Juani Leal-Sanchez ◽  
Christian Barrère; ◽  
Frédéric Cransac ◽  
...  
Keyword(s):  
Mouse Model ◽  
Infarct Size ◽  
Reperfusion Injury ◽  
Ischemia Reperfusion Injury ◽  
Ischemia Reperfusion ◽  
Dominant Negative ◽  
Dominant Negative Form ◽  
Negative Form

Requirement ofFoxD3-class signaling for neural crest determination inXenopus

Development ◽  
2001 ◽  
Vol 128 (13) ◽  
pp. 2525-2536 ◽  
Author(s):  
Noriaki Sasai ◽  
Kenji Mizuseki ◽  
Yoshiki Sasai
Keyword(s):  
Neural Crest ◽  
Dominant Negative ◽  
Related Factor ◽  
Embryonic Patterning ◽  
Loss Of Function ◽  
Upstream Regulator ◽  
Dominant Negative Form ◽  
Neural Crest Differentiation ◽  
Negative Form

Fox factors (winged-helix transcription factors) play important roles in early embryonic patterning. We show here that FoxD3 (Forkhead 6) regulates neural crest determination in Xenopus embryos. Expression of FoxD3 in the presumptive neural crest region starts at the late gastrula stage in a manner similar to that of Slug, and overlaps with that of Zic-r1. When overexpressed in the embryo and in ectodermal explants, FoxD3 induces expression of neural crest markers. Attenuation of FoxD3-related signaling by a dominant-negative FoxD3 construct (FoxD3delN) inhibits neural crest differentiation in vivo without suppressing the CNS marker Sox2. Interestingly, these loss-of-function phenotypes are reversed by coinjecting Slug. In animal cap explants, neural crest differentiation induced by Slug and Wnt3a is also inhibited by FoxD3delN but not by a dominant-negative form of XBF2. Loss-of-function studies using dominant-negative forms of FoxD3 and Slug indicate that Slug induction by Zic factors requires FoxD3-related signaling, and that FoxD3 and Slug have different requirements in inducing downstream neural crest markers. These data demonstrate that FoxD3 (or its closely related factor) is an essential upstream regulator of neural crest determination.

scholarly journals Functional Verification of Novel ELMO1 Variants By Live Imaging in Zebrafish

Blood ◽  
2021 ◽  
Vol 138 (Supplement 1) ◽  
pp. 3121-3121
Author(s):  
Rongtao Xue ◽  
Ying Wang ◽  
Tienan Wang ◽  
Mei Lyu ◽  
Guiling Mo ◽  
...  
Keyword(s):  
Cell Motility ◽  
Conflicts Of Interest ◽  
Live Imaging ◽  
Dominant Negative ◽  
Functional Verification ◽  
Transient Expression Assay ◽  
Dominant Negative Form ◽  
Reduced Mobility ◽  
Negative Form

Abstract ELMO1 (Engulfment and Cell Motility1) is a gene involved in regulating cell motility through the ELMO1-DOCK2-RAC complex. Contrary to DOCK2 (Dedicator of Cytokinesis 2) deficiency, which has been reported to be associated with immunodeficiency diseases, variants of ELMO1 have been associated with autoimmune diseases, such as diabetes and rheumatoid arthritis (RA). To explore the function of ELMO1 in immune cells and to verify the functions of novel ELMO1 variants in vivo, we established a zebrafish elmo1 mutant model. Live imaging revealed that similar to mammals, the motility of neutrophils and T-cells was largely attenuated in zebrafish mutants. Consequently, the response of neutrophils to injury or bacterial infection was significantly reduced in the mutants. Furthermore, the reduced mobility of neutrophils could be rescued by the expression of constitutively activated Rac proteins, suggesting that zebrafish elmo1 mutant functions via a conserved mechanism. With this mutant, three novel human ELMO1 variants were transiently and specifically expressed in zebrafish neutrophils. Two variants, p.E90K (c.268G>A) and p.D194G (c.581A>G) could efficiently recover the motility defect of neutrophils in the elmo1 mutant; however, the p.R354X (c.1060C>T) variant failed to rescue the mutant. Acts as a dominant-negative form, p.R354X (c.1060C>T) which failed to rescue the elmo1 mutant and inhibited neutrophil movement in siblings. Based on those results, we identified that zebrafish elmo1 played conserved roles in cell motility, similar to higher vertebrates. Using the transient-expression assay, zebrafish elmo1 mutants could serve as an effective model for human variant verification in vivo. Disclosures No relevant conflicts of interest to declare.

scholarly journals The Hippo effector TAZ cooperates with oncogenic β-catenin in experimental and human hepatoblastoma development

2019 ◽  
Author(s):  
Junyan Tao ◽  
Shu Zhang ◽  
Jie Zhang ◽  
Katja Evert ◽  
Xiaolei Li ◽  
...  
Keyword(s):  
Sleeping Beauty ◽  
Dominant Negative ◽  
Downstream Effector ◽  
Tail Vein Injection ◽  
Mesenchymal Differentiation ◽  
Dominant Negative Form ◽  
Transcription Factor 1 ◽  
Negative Form

Abstract Backgrounds: Hepatoblastoma (HB) is the most common pediatric liver tumor. Though Wnt/β-catenin and Hippo cascades are implicated in HB development, there is no study on the crosstalk of β-catenin and Hippo downstream effector TAZ in HB. Methods: The expression of TAZ and of β-catenin in human HB specimens was assessed by immunohistochemistry (IHC). The functional interplay between TAZ and β-catenin was tested through delivering either an activated form of TAZ (TAZS89A) alone or co-delivering TAZS89A and an activated form of β-catenin (∆N90-β-catenin) to mouse liver using sleeping beauty transposase via hydrodynamic tail vein injection (SBT-HTVI). In addition, the role of transcriptional enhanced associate domain (TEAD) factors, canonical Notch cascade, Yap, and the tumor modifier heat shock transcription factor 1 (HSF1) along TAZ/β-catenin-driven HB development was studied in vivo and vitro. Results: Activation of TAZ often co-occurred with that of β-catenin in clinical specimens. While overexpression of TAZS89A alone was unable to promote liver tumorigenesis, the concomitant overexpression of TAZ and ∆N90-β-catenin induced the development of HB lesions exhibiting both epithelial and mesenchymal features. Mechanistically, HB development driven by TAZ/β-catenin required TAZ interaction with TEAD factors. Furthermore, TAZ/β-catenin overexpression induced HB development in conditional Yes-associated protein knockout (Yap KO) mice, indicating that Yap activation is dispensable in this model. Activation of the Notch signaling was observed in TAZ/β-catenin mouse lesions, consistent with that reported in human HBs. Blocking of the canonical Notch cascade using the dominant negative form of RBP-J (dnRBP-J) did not inhibit TAZ/β-catenin dependent HB formation in mice, although suppressed the mesenchymal differentiation. Similarly, upregulation of HSF1 was detected in TAZ/β-catenin lesions, but its inactivation did not affect HB development. In human HB cell lines, silencing of TAZ resulted in decreased cell growth, which was reduced more substantially when TAZ knockdown was associated with suppression of either β-catenin or YAP gene. Conclusions: Overall, our study identifies TAZ as a critical oncogene in HB development and progression. Yap, Notch, and HSF1 are dispensable for TAZ/β-catenin induced HB development in mice.

scholarly journals Lymphoma-Like T Cell Infiltration in Liver Is Associated with Increased Copy Number of Dominant Negative Form of TGFβ Receptor II

PLoS ONE ◽  
2012 ◽  
Vol 7 (11) ◽  
pp. e49413 ◽  
Author(s):  
Weici Zhang ◽  
Masanobu Tsuda ◽  
Guo-Xiang Yang ◽  
Koichi Tsuneyama ◽  
Xiao-Song He ◽  
...  
Keyword(s):  
T Cell ◽  
Copy Number ◽  
Dominant Negative ◽  
Cell Infiltration ◽  
T Cell Infiltration ◽  
Dominant Negative Form ◽  
Tgfβ Receptor ◽  
Negative Form

scholarly journals The RUNX3 Tumor Suppressor Upregulates Bim in GastricEpithelial Cells Undergoing Transforming Growth Factorβ-Induced Apoptosis

2006 ◽  
Vol 26 (12) ◽  
pp. 4474-4488 ◽  
Author(s):  
Takashi Yano ◽  
Kosei Ito ◽  
Hiroshi Fukamachi ◽  
Xin-Zi Chi ◽  
Hee-Jun Wee ◽  
...  
Keyword(s):  
Tumor Suppressor ◽  
Transforming Growth Factor ◽  
Transforming Growth Factor Β ◽  
Dominant Negative ◽  
Gastric Epithelium ◽  
Dominant Negative Form ◽  
Gastric Cancer Cell Lines ◽  
Induced Apoptosis ◽  
Tgf Β1 ◽  
Negative Form

ABSTRACTGenes involved in the transforming growth factor β (TGF-β) signaling pathway are frequently altered in several types of cancers, and a gastric tumor suppressorRUNX3appears to be an integral component of this pathway. We reported previously that apoptosis is notably reduced inRunx3−/−gastric epithelial cells. In the present study, we show that a proapoptotic geneBimwas transcriptionally activated by RUNX3 in the gastric cancer cell lines SNU16 and SNU719 treated with TGF-β. The humanBimpromoter contains RUNX sites, which are required for its activation. Furthermore, a dominant negative form of RUNX3 comprised of amino acids 1 to 187 increased tumorigenicity of SNU16 by inhibiting Bim expression. InRunx3−/−mouse gastric epithelium, Bim was down-regulated, and apoptosis was reduced to the same extent as that inBim−/−gastric epithelium. We confirmed comparable expression of TGF-β1 and TGF-β receptors between wild-type andRunx3−/−gastric epithelia and reduction of Bim inTGF-β1−/−stomach. These results demonstrate that RUNX3 is responsible for transcriptional up-regulation ofBimin TGF-β-induced apoptosis.

Both Stat3-Activation and Stat3-Independent BCL2 Downregulation Are Important for Interleukin-6–Induced Apoptosis of 1A9-M Cells

Blood ◽  
1999 ◽  
Vol 93 (4) ◽  
pp. 1346-1354 ◽  
Author(s):  
Kenji Oritani ◽  
Yoshiaki Tomiyama ◽  
Paul W. Kincade ◽  
Keisuke Aoyama ◽  
Takafumi Yokota ◽  
...  
Keyword(s):  
Interleukin 6 ◽  
Cell Formation ◽  
Dominant Negative ◽  
Expression Cloning ◽  
M Cells ◽  
Macrophage Differentiation ◽  
Dominant Negative Form ◽  
Induced Apoptosis ◽  
Bcl2 Gene ◽  
Negative Form

A unique subclone of a bone marrow-derived stromal cell line, BMS2.4, produces soluble factors that inhibit proliferation of several types of hematopoietic cell lines. An understanding of these molecules may be informative about negative regulatory circuits that can potentially limit blood cell formation. We used expression cloning to identify interleukin-6 (IL-6) as one factor that suppressed growth of a pre-B–cell variant line, 1A9-M. Moreover, IL-6 induced macrophage-differentiation and apoptosis of 1A9-M cells. During this process, IL-6 downregulated expression of BCL2 in 1A9-M cells and stimulated BCL-XL expression, but had no effect on p53, Bax, or Bak gene expression. Mechanisms for transduction of IL-6–induced signals were then evaluated in IL-6–stimulated 1A9-M cells. Whereas the signal transducer and activator of transcription 3 (Stat3) was phosphorylated and activated, there was no effect on either Stat1 or Stat5. The importance of BCL2 and Stat3 on IL-6–induced macrophage-differentiation and apoptosis was studied with 1A9-M cells expressing human BCL2 or a dominant-negative form of Stat3, respectively. IL-6–induced apoptosis, but not macrophage-differentiation, was blocked by continuously expressed BCL2. A dominant-negative form of Stat3 inhibited both macrophage-differentiation and apoptosis induced by IL-6. However, diminished Stat3 activity did not prevent IL-6–induced downregulation of the BCL2 gene. Therefore, activation of Stat3 is essential for IL-6–induced macrophage-differentiation and programmed cell death in this model. Whereas overexpression of BCL2 abrogates the apoptotic response, Stat3-independent signals appear to downregulate expression of the BCL2 gene.

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