Aspirin metabolite sodium salicylate selectively inhibits transcriptional activity of ATF6α and downstream target genes

Homothorax (HTH) is a homeobox-containing protein, which plays multiple roles in the development of the embryo and the adult fly. HTH binds to the homeotic cofactor Extradenticle (EXD) and translocates it to the nucleus. Its function within the nucleus is less clear. It was shown, mainly by in vitro studies, that HTH can bind DNA as a part of ternary HTH/EXD/HOX complexes, but little is known about the transcription regulating function of HTH-containing complexes in the context of the developing fly. Here we present genetic evidence, from in vivo studies, for the transcriptional-activating function of HTH. The HTH protein was forced to act as a transcriptional repressor by fusing it to the Engrailed (EN) repression domain, or as a transcriptional activator, by fusing it to the VP16 activation domain, without perturbing its ability to translocate EXD to the nucleus. Expression of the repressing form of HTH in otherwise wild-type imaginal discs phenocopied hth loss of function. Thus, the repressing form was working as an antimorph, suggesting that normally HTH is required to activate the transcription of downstream target genes. This conclusion was further supported by the observation that the activating form of HTH caused typical hth gain-of-function phenotypes and could rescue hth loss-of-function phenotypes. Similar results were obtained with XMeis3, the Xenopus homologue of HTH, extending the known functional similarity between the two proteins. Competition experiments demonstrated that the repressing forms of HTH or XMeis3 worked as true antimorphs competing with the transcriptional activity of the native form of HTH. We also describe the phenotypic consequences of HTH antimorph activity in derivatives of the wing, labial and genital discs. Some of the described phenotypes, for example, a proboscis-to-leg transformation, were not previously associated with alterations in HTH activity. Observing the ability of HTH antimorphs to interfere with different developmental pathways may direct us to new targets of HTH. The HTH antimorph described in this work presents a new means by which the transcriptional activity of the endogenous HTH protein can be blocked in an inducible fashion in any desired cells or tissues without interfering with nuclear localization of EXD.

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PITX2 and β-Catenin Interactions Regulate Lef-1 Isoform Expression

Molecular and Cellular Biology ◽

10.1128/mcb.00315-07 ◽

2007 ◽

Vol 27 (21) ◽

pp. 7560-7573 ◽

Cited By ~ 46

Author(s):

Melanie Amen ◽

Xiaoming Liu ◽

Usha Vadlamudi ◽

Gabriela Elizondo ◽

Evan Diamond ◽

...

Keyword(s):

Cell Proliferation ◽

Cell Division ◽

Transgenic Mice ◽

Chromatin Immunoprecipitation ◽

Transcriptional Activity ◽

Target Genes ◽

Wnt Signaling Pathway ◽

Downstream Target ◽

Endogenous Expression ◽

Isoform Expression

ABSTRACT Lef-1 and PITX2 function in the Wnt signaling pathway by recruiting and interacting with β-catenin to activate target genes. Chromatin immunoprecipitation (ChIP) assays identified the Lef-1 promoter as a PITX2 downstream target. Transgenic mice expressing LacZ driven by the 2.5-kb LEF-1 promoter demonstrated expression in the tooth epithelium correlated with endogenous Lef-1 FL epithelial expression. PITX2 isoforms regulate the LEF-1 promoter, and β-catenin synergistically enhanced activation of the LEF-1 promoter in combination with PITX2 and Lef-1 isoforms. PITX2 enhances endogenous expression of the full-length β-catenin-dependent Lef-1 isoform (Lef-1 FL) while decreasing expression of the N-terminally truncated β-catenin-independent isoform. Our research revealed a novel interaction between PITX2, Lef-1, and β-catenin in which the Lef-1 β-catenin binding domain is dispensable for its interaction with PITX2. PITX2 interacts with two sites within the Lef-1 protein. Furthermore, β-catenin interacts with the PITX2 homeodomain and Lef-1 interacts with the PITX2 C-terminal tail. Lef-1 and β-catenin interact simultaneously and independently with PITX2 through two different sites to regulate PITX2 transcriptional activity. These data support a role for PITX2 in cell proliferation, migration, and cell division through differential Lef-1 isoform expression and interactions with Lef-1 and β-catenin.

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ARNT-dependent HIF-2 transcriptional activity is not sufficient to regulate downstream target genes in neuroblastoma

Experimental Cell Research ◽

10.1016/j.yexcr.2020.111845 ◽

2020 ◽

Vol 388 (2) ◽

pp. 111845 ◽

Cited By ~ 8

Author(s):

Camilla U. Persson ◽

Kristoffer von Stedingk ◽

Elina Fredlund ◽

Daniel Bexell ◽

Sven Påhlman ◽

...

Keyword(s):

Transcriptional Activity ◽

Target Genes ◽

Downstream Target

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FAM64A positively regulates STAT3 activity to promote Th17 differentiation and colitis-associated carcinogenesis

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1814336116 ◽

2019 ◽

Vol 116 (21) ◽

pp. 10447-10452 ◽

Cited By ~ 8

Author(s):

Zhi-Sheng Xu ◽

Hong-Xia Zhang ◽

Wei-Wei Li ◽

Yong Ran ◽

Tian-Tian Liu ◽

...

Keyword(s):

Transcriptional Activity ◽

Target Genes ◽

Dextran Sulfate ◽

Dextran Sulfate Sodium ◽

Inflammatory Diseases ◽

Autoimmune Encephalomyelitis ◽

Downstream Target ◽

Physiological Processes ◽

Th17 Differentiation ◽

Experimental Autoimmune

STAT3 is a transcription factor that plays central roles in various physiological processes, including differentiation of Th cells. Its deregulation results in serious diseases, including inflammatory diseases and cancer. The mechanisms related to how STAT3 activity is regulated remain enigmatic. Here we show that overexpression of FAM64A potentiates IL-6–induced activation of STAT3 and expression of downstream target genes, whereas deficiency of FAM64A has the opposite effects. FAM64A interacts with STAT3 in the nucleus and regulates binding of STAT3 to the promoters of its target genes. Deficiency of Fam64a significantly impairs differentiation of Th17 but not Th1 or induced regulatory T cells (iTreg). In addition, Fam64a deficiency attenuates experimental autoimmune encephalomyelitis (EAE) and dextran sulfate sodium (DSS)-induced colitis, which is correlated with decreased differentiation of Th17 cells and production of proinflammatory cytokines. Furthermore, Fam64a deficiency suppresses azoxymethane (AOM)/DSS-induced colitis-associated cancer (CAC) in mice. These findings suggest that FAM64A regulates Th17 differentiation and colitis and inflammation-associated cancer by modulating transcriptional activity of STAT3.

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n-Propyl gallate activates hypoxia-inducible factor 1 by modulating intracellular oxygen-sensing systems

Biochemical Journal ◽

10.1042/bj20070824 ◽

2008 ◽

Vol 411 (1) ◽

pp. 97-105 ◽

Cited By ~ 13

Author(s):

Motohide Kimura ◽

Satoshi Takabuchi ◽

Tomoharu Tanaka ◽

Miyahiko Murata ◽

Kenichiro Nishi ◽

...

Keyword(s):

Propyl Gallate ◽

Transcriptional Activity ◽

Target Genes ◽

Cultured Cells ◽

Oxygen Sensing ◽

Hypoxia Inducible Factor ◽

Downstream Target ◽

Hypoxia Inducible Factor 1

HIF-1 (hypoxia-inducible factor 1) is a master regulator of cellular adaptive responses to hypoxia. The expression and transcriptional activity of the HIF-1α subunit is stringently controlled by intracellular oxygen tension through the action of prolyl and asparaginyl hydroxylases. In the present study we demonstrate that PG (n-propyl gallate) activates HIF-1 and expression of its downstream target genes under normoxic conditions in cultured cells and in mice. The stability and transcriptional activity of HIF-1α are increased by PG. PG treatment inhibits the interaction between HIF-1α and VHL (von Hippel–Lindau protein) and promotes the interaction between HIF-1α and p300, indicating that PG inhibits the activity of both prolyl and asparaginyl HIF-1α hydroxylases. We conclude that PG activates HIF-1 and enhances the resultant gene expression by directly affecting the intracellular oxygen sensing system in vitro and in vivo and that PG represents a lead compound for the development of a non-toxic activator of HIF-1.

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PFKFB4 promotes lung adenocarcinoma progression via phosphorylating and activating transcriptional coactivator SRC-2

BMC Pulmonary Medicine ◽

10.1186/s12890-021-01420-x ◽

2021 ◽

Vol 21 (1) ◽

Author(s):

Jiguang Meng ◽

Xuxin Chen ◽

Zhihai Han

Keyword(s):

Lung Adenocarcinoma ◽

Transcriptional Activity ◽

Cell Counting ◽

Migration And Invasion ◽

Transcriptional Coactivator ◽

Downstream Target ◽

Steroid Receptor Coactivator ◽

Adenocarcinoma Cells ◽

Family Protein ◽

Lung Adenocarcinoma Cells

Abstract Background To investigate the role and its potential mechanism of 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase 4 (PFKFB4) in lung adenocarcinoma. Methods Co-immunoprecipitation was performed to analyze the interaction between PFKFB4 and SRC-2. Western blot was used to investigate the phosphorylation of steroid receptor coactivator-2 (SRC-2) on the condition that PFKFB4 was knockdown. Transcriptome sequencing was performed to find the downstream target of SRC-2. Cell Counting Kit-8 (CCK-8) assay, transwell assay and transwell-matrigel assay were used to examine the proliferation, migration and invasion abilities in A549 and NCI-H1975 cells with different treatment. Results In our study we found that PFKFB4 was overexpressed in lung adenocarcinoma associated with SRC family protein and had an interaction with SRC-2. PFKFB4 could phosphorylate SRC-2 at Ser487, which altered SRC-2 transcriptional activity. Functionally, PFKFB4 promoted lung adenocarcinoma cells proliferation, migration and invasion by phosphorylating SRC-2. Furthermore, we identified that CARM1 was transcriptionally regulated by SRC-2 and involved in PFKFB4-SRC-2 axis on lung adenocarcinoma progression. Conclusions Our research reveal that PFKFB4 promotes lung adenocarcinoma cells proliferation, migration and invasion via enhancing phosphorylated SRC-2-mediated CARM1 expression.

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Lysine acetyltransferase Tip60 acetylates the APP adaptor Fe65 to increase its transcriptional activity

Biological Chemistry ◽

10.1515/hsz-2020-0279 ◽

2020 ◽

Vol 0 (0) ◽

Author(s):

Sabine Probst ◽

Florian Riese ◽

Larissa Kägi ◽

Maik Krüger ◽

Natalie Russi ◽

...

Keyword(s):

Transcriptional Activity ◽

Target Genes ◽

Adaptor Protein ◽

Proteolytic Processing ◽

Class Iii ◽

Lysine Deacetylase ◽

Lysine Residues ◽

Lysine Acetyltransferase ◽

Complex Forms ◽

Spot Formation

AbstractProteolytic processing of the amyloid precursor protein (APP) releases the APP intracellular domain (AICD) from the membrane. Bound to the APP adaptor protein Fe65 and the lysine acetyltransferase (KAT) Tip60, AICD translocates to the nucleus. Here, the complex forms spherical condensates at sites of endogenous target genes, termed AFT spots (AICD-Fe65-Tip60). We show that loss of Tip60 KAT activity prevents autoacetylation, reduces binding of Fe65 and abolishes Fe65-mediated stabilization of Tip60. Autoacetylation is a prerequisite for AFT spot formation, with KAT-deficient Tip60 retained together with Fe65 in speckles. We identify lysine residues 204 and 701 of Fe65 as acetylation targets of Tip60. We do not detect acetylation of AICD. Mutation of Fe65 K204 and K701 to glutamine, mimicking acetylation-induced charge neutralization, increases the transcriptional activity of Fe65 whereas Tip60 inhibition reduces it. The lysine deacetylase (KDAC) class III Sirt1 deacetylates Fe65 and pharmacological modulation of Sirt1 activity regulates Fe65 transcriptional activity. A second acetylation/deacetylation cycle, conducted by CBP and class I/II KDACs at different lysine residues, regulates stability of Fe65. This is the first report describing a role for acetylation in the regulation of Fe65 transcriptional activity, with Tip60 being the only KAT tested that supports AFT spot formation.

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Drosophila Gain-of-Function Mutant RTK Torso Triggers Ectopic Dpp and STAT Signaling

Genetics ◽

10.1093/genetics/164.1.247 ◽

2003 ◽

Vol 164 (1) ◽

pp. 247-258 ◽

Cited By ~ 1

Author(s):

Jinghong Li ◽

Willis X Li

Keyword(s):

Tyrosine Kinases ◽

Target Genes ◽

Tor Signaling ◽

Gain Of Function ◽

Essential Requirement ◽

Downstream Target ◽

Rtk Signaling ◽

Genome Wide ◽

A Genome ◽

Genomic Regions

Abstract Overactivation of receptor tyrosine kinases (RTKs) has been linked to tumorigenesis. To understand how a hyperactivated RTK functions differently from wild-type RTK, we conducted a genome-wide systematic survey for genes that are required for signaling by a gain-of-function mutant Drosophila RTK Torso (Tor). We screened chromosomal deficiencies for suppression of a gain-of-function mutation tor (torGOF), which led to the identification of 26 genomic regions that, when in half dosage, suppressed the defects caused by torGOF. Testing of candidate genes in these regions revealed many genes known to be involved in Tor signaling (such as those encoding the Ras-MAPK cassette, adaptor and structural molecules of RTK signaling, and downstream target genes of Tor), confirming the specificity of this genetic screen. Importantly, this screen also identified components of the TGFβ (Dpp) and JAK/STAT pathways as being required for TorGOF signaling. Specifically, we found that reducing the dosage of thickveins (tkv), Mothers against dpp (Mad), or STAT92E (aka marelle), respectively, suppressed torGOF phenotypes. Furthermore, we demonstrate that in torGOF embryos, dpp is ectopically expressed and thus may contribute to the patterning defects. These results demonstrate an essential requirement of noncanonical signaling pathways for a persistently activated RTK to cause pathological defects in an organism.

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Emerging multifaceted roles of BAP1 complexes in biological processes

Cell Death Discovery ◽

10.1038/s41420-021-00406-2 ◽

2021 ◽

Vol 7 (1) ◽

Author(s):

Aileen Patricia Szczepanski ◽

Lu Wang

Keyword(s):

Transcriptional Repression ◽

Target Genes ◽

Regulatory Mechanisms ◽

Biological Processes ◽

Multiprotein Complex ◽

Downstream Target ◽

Evolutionarily Conserved ◽

Complex Forms ◽

Polycomb Repressive Complex 1

AbstractHistone H2AK119 mono-ubiquitination (H2AK119Ub) is a relatively abundant histone modification, mainly catalyzed by the Polycomb Repressive Complex 1 (PRC1) to regulate Polycomb-mediated transcriptional repression of downstream target genes. Consequently, H2AK119Ub can also be dynamically reversed by the BAP1 complex, an evolutionarily conserved multiprotein complex that functions as a general transcriptional activator. In previous studies, it has been reported that the BAP1 complex consists of important biological roles in development, metabolism, and cancer. However, identifying the BAP1 complex’s regulatory mechanisms remains to be elucidated due to its various complex forms and its ability to target non-histone substrates. In this review, we will summarize recent findings that have contributed to the diverse functional role of the BAP1 complex and further discuss the potential in targeting BAP1 for therapeutic use.

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