scholarly journals Negative Regulatory Loop between Microphthalmia-Associated Transcription Factor (MITF) and Notch Signaling

2019 ◽  
Vol 20 (3) ◽  
pp. 576 ◽  
Author(s):  
Tamar Golan ◽  
Carmit Levy
Keyword(s):  
Transcription Factor ◽  
Notch Signaling ◽  
Transcriptional Activity ◽  
Treatment Resistance ◽  
Gene Encoding ◽  
Reciprocal Interactions ◽  
Melanoma Progression ◽  
Regulatory Loop ◽  
Signaling Activation ◽  
Mitf Expression

Melanoma, a melanocyte-origin neoplasm, is a highly metastatic and treatment-resistance cancer. While it is well established that notch signaling activation promotes melanoma progression, little is known about the reciprocal interactions between Notch signaling and melanoma-specific pathways. Here we reveal a negative regulatory loop between Notch signaling and microphthalmia-associated transcription factor (MITF), the central regulator of melanoma progression and the driver of melanoma plasticity. We further demonstrate that Notch signaling activation, in addition to the known competition-based repression mechanism of MITF transcriptional activity, inhibits the transcription of MITF, leading to a decrease in MITF expression. We also found that MITF binds to the promoter of the gene encoding the master regulator of Notch signaling, recombination signal binding protein J kappa (RBPJK), leading to its upregulation. Our findings suggest that, once activated, Notch signaling represses MITF signaling to maintain the melanoma invasiveness and metastatic phenotype.

AML1/Runx1 rescues Notch1-null mutation-induced deficiency of para-aortic splanchnopleural hematopoiesis

Blood ◽  
2006 ◽  
Vol 108 (10) ◽  
pp. 3329-3334 ◽  
Author(s):  
Masahiro Nakagawa ◽  
Motoshi Ichikawa ◽  
Keiki Kumano ◽  
Susumu Goyama ◽  
Masahito Kawazu ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Notch Signaling ◽  
Culture System ◽  
Transcriptional Activity ◽  
Null Mutation ◽  
Hematopoietic Development ◽  
Retroviral Transfer ◽  
Definitive Hematopoiesis ◽  
Runx1 Expression

Abstract The Notch1-RBP-Jκ and the transcription factor Runx1 pathways have been independently shown to be indispensable for the establishment of definitive hematopoiesis. Importantly, expression of Runx1 is down-regulated in the para-aortic splanchnopleural (P-Sp) region of Notch1- and Rbpsuh-null mice. Here we demonstrate that Notch1 up-regulates Runx1 expression and that the defective hematopoietic potential of Notch1-null P-Sp cells is successfully rescued in the OP9 culture system by retroviral transfer of Runx1. We also show that Hes1, a known effector of Notch signaling, potentiates Runx1-mediated transactivation. Together with the recent findings in zebrafish, Runx1 is postulated to be a cardinal down-stream mediator of Notch signaling in hematopoietic development throughout vertebrates. Our findings also suggest that Notch signaling may modulate both expression and transcriptional activity of Runx1.

scholarly journals Role of Jagged1-mediated Notch Signaling Activation in the Differentiation and Stratification of the Human Limbal Epithelium

Cells ◽  
2020 ◽  
Vol 9 (9) ◽  
pp. 1945
Author(s):  
Sheyla González ◽  
Maximilian Halabi ◽  
David Ju ◽  
Matthew Tsai ◽  
Sophie X. Deng
Keyword(s):  
Notch Signaling ◽  
Progenitor Cell ◽  
Basal Layer ◽  
Notch Signaling Pathway ◽  
Basal Cells ◽  
Proliferation Markers ◽  
Limbal Epithelium ◽  
Asymmetric Divisions ◽  
Signaling Activation

The Notch signaling pathway plays a key role in proliferation and differentiation. We investigated the effect of Jagged 1 (Jag1)-mediated Notch signaling activation in the human limbal stem/progenitor cell (LSC) population and the stratification of the limbal epithelium in vitro. After Notch signaling activation, there was a reduction in the amount of the stem/progenitor cell population, epithelial stratification, and expression of proliferation markers. There was also an increase of the corneal epithelial differentiation. In the presence of Jag1, asymmetric divisions were decreased, and the expression pattern of the polarity protein Par3, normally present at the apical-lateral membrane of basal cells, was dispersed in the cells. We propose a mechanism in which Notch activation by Jag1 decreases p63 expression at the basal layer, which in turn reduces stratification by decreasing the number of asymmetric divisions and increases differentiation.

scholarly journals The apple C2H2-type zinc finger transcription factor MdZAT10 positively regulates JA-induced leaf senescence by interacting with MdBT2

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Kuo Yang ◽  
Jian-Ping An ◽  
Chong-Yang Li ◽  
Xue-Na Shen ◽  
Ya-Jing Liu ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Transcription Factor ◽  
Liquid Chromatography ◽  
Zinc Finger ◽  
Leaf Senescence ◽  
Transcriptional Activity ◽  
Molecular Mechanisms ◽  
Liquid Chromatography Mass Spectrometry ◽  
Zinc Finger Transcription Factor ◽  
Insight Into

AbstractJasmonic acid (JA) plays an important role in regulating leaf senescence. However, the molecular mechanisms of leaf senescence in apple (Malus domestica) remain elusive. In this study, we found that MdZAT10, a C2H2-type zinc finger transcription factor (TF) in apple, markedly accelerates leaf senescence and increases the expression of senescence-related genes. To explore how MdZAT10 promotes leaf senescence, we carried out liquid chromatography/mass spectrometry screening. We found that MdABI5 physically interacts with MdZAT10. MdABI5, an important positive regulator of leaf senescence, significantly accelerated leaf senescence in apple. MdZAT10 was found to enhance the transcriptional activity of MdABI5 for MdNYC1 and MdNYE1, thus accelerating leaf senescence. In addition, we found that MdZAT10 expression was induced by methyl jasmonate (MeJA), which accelerated JA-induced leaf senescence. We also found that the JA-responsive protein MdBT2 directly interacts with MdZAT10 and reduces its protein stability through ubiquitination and degradation, thereby delaying MdZAT10-mediated leaf senescence. Taken together, our results provide new insight into the mechanisms by which MdZAT10 positively regulates JA-induced leaf senescence in apple.

scholarly journals The AML-associated K313 mutation enhances C/EBPα activity by leading to C/EBPα overexpression

2021 ◽  
Vol 12 (7) ◽  
Author(s):  
Ian Edward Gentle ◽  
Isabel Moelter ◽  
Mohamed Tarek Badr ◽  
Konstanze Döhner ◽  
Michael Lübbert ◽  
...  
Keyword(s):  
Gene Expression ◽  
Cell Culture ◽  
Transcription Factor ◽  
Transcription Factors ◽  
Transcriptional Activity ◽  
Target Gene ◽  
Wild Type ◽  
Elevated Expression ◽  
Factor C ◽  
Acute Myeloid

AbstractMutations in the transcription factor C/EBPα are found in ~10% of all acute myeloid leukaemia (AML) cases but the contribution of these mutations to leukemogenesis is incompletely understood. We here use a mouse model of granulocyte progenitors expressing conditionally active HoxB8 to assess the cell biological and molecular activity of C/EBPα-mutations associated with human AML. Both N-terminal truncation and C-terminal AML-associated mutations of C/EBPα substantially altered differentiation of progenitors into mature neutrophils in cell culture. Closer analysis of the C/EBPα-K313-duplication showed expansion and prolonged survival of mutant C/EBPα-expressing granulocytes following adoptive transfer into mice. C/EBPα-protein containing the K313-mutation further showed strongly enhanced transcriptional activity compared with the wild-type protein at certain promoters. Analysis of differentially regulated genes in cells overexpressing C/EBPα-K313 indicates a strong correlation with genes regulated by C/EBPα. Analysis of transcription factor enrichment in the differentially regulated genes indicated a strong reliance of SPI1/PU.1, suggesting that despite reduced DNA binding, C/EBPα-K313 is active in regulating target gene expression and acts largely through a network of other transcription factors. Strikingly, the K313 mutation caused strongly elevated expression of C/EBPα-protein, which could also be seen in primary K313 mutated AML blasts, explaining the enhanced C/EBPα activity in K313-expressing cells.

scholarly journals CSIG-13. TRPM7 INDUCES TUMORIGENESIS AND STEMNESS THROUGH NOTCH ACTIVATION IN GLIOMA

2020 ◽  
Vol 22 (Supplement_2) ◽  
pp. ii30-ii30
Author(s):  
Jingwei Wan ◽  
Alyssa Guo ◽  
Mingli Liu
Keyword(s):  
Notch Signaling ◽  
Glioma Cell ◽  
Glioma Cells ◽  
Inhibitory Effect ◽  
Notch Signaling Pathway ◽  
Normal Brain ◽  
Diffuse Astrocytoma ◽  
Notch1 Signaling ◽  
Signaling Activation ◽  
Proliferation And Invasion

Abstract Our group found that the inhibitory effect of TRPM7 on proliferation and invasion of human glioma cell is mediated by multiple mechanisms. TRPM7 regulates miR-28-5p expression, which suppresses cell proliferation and invasion in glioma cells by targeting Ras-related protein Rap1b. In particular, our group found that TRPM7 channels regulate glioma stem cell (GSC) growth/proliferation through STAT3 and Notch signaling. However, which Notch component(s) is crucial for its activity regulated by TRPM7, and its relationship with other GSC markers, such as CD133 and ALDH1, remain unclear. In the current project, we elucidate the mechanisms of TRMP7’s regulation of Notch signaling pathway that contribute to the development and progression of glioma and maintenance of self-renewal and tumorigenicity of GSC using multiple glioma cell lines (GC) with different molecular subtypes and GSCs derived from the GC lines. 1) We first analyzed TRPM7 expression using the Oncomine database (https://www.oncomine.org) and found that the TRPM7 mRNA expression is significantly increased in anaplastic astrocytoma, diffuse astrocytoma, and GBM patients compared to that in normal brain tissue controls. 2) TRPM7 is expressed in GBM, and its channel activity is correlated with Notch1 activation. Inhibition of TRPM7 downregulates Notch1 signaling, while upregulation of TRPM7 upregulates Notch1 signaling. 3) GSC markers, CD133 and ALDH1, are correlated with TRPM7 in GBM. 4) Targeting TRPM7 suppresses the growth and proliferation of glioma cells through G1/S arrests and apoptosis of glioma cells. 5) Targeting Notch1 suppresses the TRPM7-induced growth and proliferation of glioma cells, as well as the expression of GSC markers CD133 and ALDH1. In summary, TRPM7 is responsible for sustained Notch signaling activation, enhanced expression of GSC markers, and regulation of glioma stemness, which contribute to malignant glioma cell growth and invasion. Notch1 and ligand DII4 are key components that contribute GSC stemness.

scholarly journals Differential activation mechanisms of two isoforms of Gcr1 transcription factor generated from spliced and un-spliced transcripts in Saccharomyces cerevisiae

2020 ◽  
Author(s):  
Seungwoo Cha ◽  
Chang Pyo Hong ◽  
Hyun Ah Kang ◽  
Ji-Sook Hahn
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Transcription Factor ◽  
Target Genes ◽  
Gene Encoding ◽  
Metabolic Switch ◽  
Differential Activation ◽  
N Terminus ◽  
Activation Mechanisms ◽  
In Trans ◽  
Separate Activation

Abstract Gcr1, an important transcription factor for glycolytic genes in Saccharomyces cerevisiae, was recently revealed to have two isoforms, Gcr1U and Gcr1S, produced from un-spliced and spliced transcripts, respectively. In this study, by generating strains expressing only Gcr1U or Gcr1S using the CRISPR/Cas9 system, we elucidate differential activation mechanisms of these two isoforms. The Gcr1U monomer forms an active complex with its coactivator Gcr2 homodimer, whereas Gcr1S acts as a homodimer without Gcr2. The USS domain, 55 residues at the N-terminus existing only in Gcr1U, inhibits dimerization of Gcr1U and even acts in trans to inhibit Gcr1S dimerization. The Gcr1S monomer inhibits the metabolic switch from fermentation to respiration by directly binding to the ALD4 promoter, which can be restored by overexpression of the ALD4 gene, encoding a mitochondrial aldehyde dehydrogenase required for ethanol utilization. Gcr1U and Gcr1S regulate almost the same target genes, but show unique activities depending on growth phase, suggesting that these isoforms play differential roles through separate activation mechanisms depending on environmental conditions.

Sign in / Sign up

Export Citation Format

Share Document