Energy deprivation and a deficiency in downstream metabolic target genes during the onset of embryonic heart failure in RXRalpha−/− embryos

Development ◽  
1998 ◽  
Vol 125 (3) ◽  
pp. 533-544 ◽  
Author(s):  
P. Ruiz-Lozano ◽  
S.M. Smith ◽  
G. Perkins ◽  
S.W. Kubalak ◽  
G.R. Boss ◽  
...  
Keyword(s):  
Target Genes ◽  
Subtractive Hybridization ◽  
Causative Factor ◽  
Mutant Mice ◽  
Intermediary Metabolism ◽  
Wild Type ◽  
Energy Deficiency ◽  
Downstream Target ◽  
Ultrastructural Studies ◽  
Energy Deprivation

RXRalpha null mutant mice display ocular and cardiac malformations, liver developmental delay, and die from cardiac failure around embryonic day (E) 14.5 pc. To dissect the molecular basis of the RXRalpha-associated cardiomyopathy, we performed subtractive hybridization and systematically characterized putative downstream target genes that were selectively lacking in the mutant embryos, both at early (E10.5) and late (E13.5) stages of mouse embryonic development. Approximately 50% of the subtracted clones (61/115) encoded proteins involved in intermediary metabolism and electron transport, suggesting an energy deficiency in the RXRalpha−/− embryos. In particular, clone G1, which encodes subunit 14.5b of the NADH-ubiquinone dehydrogenase complex, displayed a dose-dependent expression in the wild-type, heterozygous and RXRalpha mutant mice. This gene was also downregulated in a retinoid-deficient rat embryo model. ATP content and medium Acyl-CoA dehydrogenase mRNA were lower in RXRalpha mutant hearts compared to wild-type mice. Ultrastructural studies showed that the density of mitochondria per myocyte was higher in the RXRalpha mutant compared to wild-type littermates. We propose a model whereby defects in intermediary metabolism may be a causative factor of the RXRalpha−/− phenotype and resembles an embryonic form of dilated cardiomyopathy.

Overexpression of Foxf2 in adipose tissue is associated with lower levels of IRS1 and decreased glucose uptake in vivo

2010 ◽  
Vol 298 (3) ◽  
pp. E548-E554 ◽  
Author(s):  
Rickard Westergren ◽  
Daniel Nilsson ◽  
Mikael Heglind ◽  
Zahra Arani ◽  
Mats Grände ◽  
...  
Keyword(s):  
Adipose Tissue ◽  
Glucose Tolerance ◽  
Glucose Uptake ◽  
Target Genes ◽  
Whole Body ◽  
Wild Type ◽  
Intravenous Glucose ◽  
Downstream Target ◽  
Protein Levels

Many members of the forkhead genes family of transcription factors have been implicated as important regulators of metabolism, in particular, glucose homeostasis, e.g., Foxo1, Foxa3, and Foxc2. The purpose of this study was to exploit the possibility that yet unknown members of this gene family play a role in regulating glucose tolerance in adipocytes. We identified Foxf2 in a screen for adipose-expressed forkhead genes. In vivo overexpression of Foxf2 in an adipose tissue-restricted fashion demonstrated that such mice display a significantly induced insulin secretion in response to an intravenous glucose load compared with wild-type littermates. In response to increased Foxf2 expression, insulin receptor substrate 1 (IRS1) mRNA and protein levels are significantly downregulated in adipocytes; however, the ratio of serine vs. tyrosine phosphorylation of IRS1 seems to remain unaffected. Furthermore, adipocytes overexpressing Foxf2 have a significantly lower insulin-mediated glucose uptake compared with wild-type adipocytes. These findings argue that Foxf2 is a previously unrecognized regulator of cellular and systemic whole body glucose tolerance, at least in part, due to lower levels of IRS1. Foxf2 and its downstream target genes can provide new insights with regard to identification of novel therapeutic targets.

scholarly journals Identification of a Mouse Homolog of the Human BTEB2Transcription Factor as a β-Catenin-Independent Wnt-1-Responsive Gene

2001 ◽  
Vol 21 (2) ◽  
pp. 562-574 ◽  
Author(s):  
Lisa Taneyhill Ziemer ◽  
Diane Pennica ◽  
Arnold J. Levine
Keyword(s):  
Cell Line ◽  
Cell Fate ◽  
Target Genes ◽  
Wild Type Mouse ◽  
Subtractive Hybridization ◽  
Parental Cell ◽  
Mammary Tissue ◽  
Parental Cell Line ◽  
Mouse Homolog ◽  
Downstream Target

ABSTRACT The Wnt/Wg signaling pathway functions during development to regulate cell fate determination and patterning in various organisms. Two pathways are reported to lie downstream of Wnt signaling in vertebrates. The canonical pathway relies on the activation of target genes through the β-catenin–Lef/TCF complex, while the noncanonical pathway employs the activation of protein kinase C (PKC) and increases in intracellular calcium to induce target gene expression. cDNA subtractive hybridization between a cell line that overexpresses Wnt-1 (C57MG/Wnt-1) and the parental cell line (C57MG) was performed to identify downstream target genes of Wnt-1 signaling. Among the putative Wnt-1 target genes, we have identified a mouse homolog of the gene encoding human transcription factor basic transcription element binding protein 2 (mBTEB2). ThemBTEB2 transcript is found at high levels in mammary tissue taken from a transgenic mouse overexpressing Wnt-1 (both tissue prior to active proliferation and tumor tissue) but is barely detectable in wild-type mouse mammary glands. The regulation of mBTEB2 by Wnt-1 signaling in tissue culture occurs through a β-catenin–Lef/TCF-independent mechanism, as it is instead partially regulated by PKC. The Wnt-1-induced, PKC-dependent activation of mouse BTEB2 in C57MG cells, as well as the ability of Wnt-1 to stabilize β-catenin in these cells, is consistent with the hypothesis that both the noncanonical and canonical Wnt pathways are activated concomitantly in the same cell. These results suggest that mBTEB2 is a biologically relevant target of Wnt-1 signaling that is activated through a β-catenin-independent, PKC-sensitive pathway in response to Wnt-1.

scholarly journals Identification of Botrytis cinerea Genes Up-Regulated During Infection and Controlled by the Gα Subunit BCG1 Using Suppression Subtractive Hybridization (SSH)

2004 ◽  
Vol 17 (5) ◽  
pp. 537-546 ◽  
Author(s):  
Christian Schulze Gronover ◽  
Corinna Schorn ◽  
Bettina Tudzynski
Keyword(s):  
Botrytis Cinerea ◽  
Differentially Expressed Genes ◽  
Suppression Subtractive Hybridization ◽  
Target Genes ◽  
Subtractive Hybridization ◽  
Differentially Expressed ◽  
Wild Type ◽  
In Planta ◽  
Cell Wall Degrading Enzymes ◽  
Fungal Genes

The Gα subunit BCG1 plays an important role during the infection of host plants by Botrytis cinerea. Δbcg1 Mutants are able to conidiate, penetrate host leaves, and produce small primary lesions. However, in contrast to the wild type, the mutants completely stop invasion of plant tissue at this stage; secondary lesions have never been observed. Suppression subtractive hybridization (SSH) was used to identify fungal genes whose expression on the host plant is specifically affected in bcg1 mutants. Among the 22 differentially expressed genes, we found those which were predicted to encode proteases, enzymes involved in secondary metabolism, and others encoding cell wall-degrading enzymes. All these genes are highly expressed during infection in the wild type but not in the mutant. However, the genes are expressed in both the wild type and the mutant under certain conditions in vitro. Most of the BCG1-controlled genes are still expressed in adenylate cyclase (bac) mutants in planta, suggesting that BCG1 is involved in at least one additional signaling cascade in addition to the cAMP-depending pathway. In a second SSH approach, 1,500 clones were screened for those that are specifically induced by the wild type during the infection of bean leaves. Of the 22 BCG1-controlled genes, 11 also were found in the in planta SSH library. Therefore, SSH technology can be successfully applied to identify target genes of signaling pathways and differentially expressed genes in planta.

scholarly journals γ-Catenin is regulated by the APC tumor suppressor and its oncogenic activity is distinct from that of β-catenin

2000 ◽  
Vol 14 (11) ◽  
pp. 1319-1331 ◽  
Author(s):  
Frank T. Kolligs ◽  
Barbara Kolligs ◽  
Karen M. Hajra ◽  
Gang Hu ◽  
Masachika Tani ◽  
...  
Keyword(s):  
Tumor Suppressor ◽  
Wnt Signaling ◽  
Target Genes ◽  
Wnt Signaling Pathway ◽  
Tumor Suppressor Protein ◽  
Wild Type ◽  
Downstream Target ◽  
Amino Terminal ◽  
Transforming Activity ◽  
Altered Regulation

β-Catenin and γ-catenin (plakoglobin), vertebrate homologs of Drosophila armadillo, function in cell adhesion and the Wnt signaling pathway. In colon and other cancers, mutations in the APC tumor suppressor protein orβ-catenin's amino terminus stabilizeβ-catenin, enhancing its ability to activate transcription of Tcf/Lef target genes. Thoughβ- and γ-catenin have analogous structures and functions and like binding to APC, evidence that γ-catenin has an important role in cancer has been lacking. We report here that APC regulates bothβ- and γ-catenin andγ-catenin functions as an oncogene. In contrast to β-catenin, for which only amino-terminal mutated forms transform RK3E epithelial cells, wild-type and several amino-terminal mutated forms of γ-catenin had similar transforming activity. γ-Catenin's transforming activity, like β-catenin's, was dependent on Tcf/Lef function. However, in contrast toβ-catenin, γ-catenin strongly activated c-Myc expression and c-Myc function was crucial for γ-catenin transformation. Our findings suggest APC mutations alter regulation of bothβ- and γ-catenin, perhaps explaining why the frequency of APC mutations in colon cancer far exceeds that of β-catenin mutations. Elevated c-Myc expression in cancers with APC defects may be due to altered regulation of both β- andγ-catenin. Furthermore, the data implyβ- and γ-catenin may have distinct roles in Wnt signaling and cancer via differential effects on downstream target genes.

scholarly journals Identification of homeotic target genes in Drosophila melanogaster including nervy, a proto-oncogene homologue.

Genetics ◽  
1995 ◽  
Vol 140 (2) ◽  
pp. 573-586 ◽  
Author(s):  
P G Feinstein ◽  
K Kornfeld ◽  
D S Hogness ◽  
R S Mann
Keyword(s):  
Gene Expression ◽  
Target Gene ◽  
Target Genes ◽  
Early Stage ◽  
Gene Expression Pattern ◽  
Morphological Characteristics ◽  
Subtractive Hybridization ◽  
Homeotic Genes ◽  
Target Gene Expression ◽  
Downstream Target

Abstract In Drosophila, the specific morphological characteristics of each segment are determined by the homeotic genes that regulate the expression of downstream target genes. We used a subtractive hybridization procedure to isolate activated target genes of the homeotic gene Ultrabithorax (Ubx). In addition, we constructed a set of mutant genotypes that measures the regulatory contribution of individual homeotic genes to a complex target gene expression pattern. Using these mutants, we demonstrate that homeotic genes can regulate target gene expression at the start of gastrulation, suggesting a previously unknown role for the homeotic genes at this early stage. We also show that, in abdominal segments, the levels of expression for two target genes increase in response to high levels of Ubx, demonstrating that the normal down-regulation of Ubx in these segments is functional. Finally, the DNA sequence of cDNAs for one of these genes predicts a protein that is similar to a human proto-oncogene involved in acute myeloid leukemias. These results illustrate potentially general rules about the homeotic control of target gene expression and suggest that subtractive hybridization can be used to isolate interesting homeotic target genes.

scholarly journals Alopecia in Harlequin mutant mice is associated with reduced AIF protein levels and expression of retroviral elements

2020 ◽  
Author(s):  
Maik Hintze ◽  
Sebastian Griesing ◽  
Marion Michels ◽  
Birgit Blanck ◽  
Lena Wischhof ◽  
...  
Keyword(s):  
Hair Growth ◽  
Transcriptional Regulators ◽  
Mutant Mice ◽  
Wild Type ◽  
Protein Levels ◽  
Expression Of Genes ◽  
Genes Encoding ◽  
Keratinocyte Cell ◽  
Apoptosis Inducing Factor ◽  
Hair Cortex

AbstractWe investigated the contribution of apoptosis-inducing factor (AIF), a key regulator of mitochondrial biogenesis, in supporting hair growth. We report that pelage abnormalities developed during hair follicle (HF) morphogenesis in Harlequin (Hq) mutant mice. Fragility of the hair cortex was associated with decreased expression of genes encoding structural hair proteins, though key transcriptional regulators of HF development were expressed at normal levels. Notably, Aifm1 (R200 del) knockin males and Aifm1(R200 del)/Hq females showed minor hair defects, despite substantially reduced AIF levels. Furthermore, we cloned the integrated ecotropic provirus of the Aifm1Hq allele. We found that its overexpression in wild-type keratinocyte cell lines led to down-regulation of HF-specific Krt84 and Krtap3-3 genes without altering Aifm1 or epidermal Krt5 expression. Together, our findings imply that pelage paucity in Hq mutant mice is mechanistically linked to severe AIF deficiency and is associated with the expression of retroviral elements that might potentially influence the transcriptional regulation of structural hair proteins.

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

Genetics ◽  
2003 ◽  
Vol 164 (1) ◽  
pp. 247-258 ◽  
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.

scholarly journals Emerging multifaceted roles of BAP1 complexes in biological processes

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.

scholarly journals MODL-16. ABEMACICLIB, A SELECTIVE CDK4/6 INHIBITOR, RESTRICTS GROWTH OF PEDIATRIC GLIAL-LINEAGE TUMORS IN VITRO AND IN VIVO

2020 ◽  
Vol 22 (Supplement_3) ◽  
pp. iii414-iii414
Author(s):  
Muh-Lii Liang ◽  
Tsung-Han Hsieh ◽  
Tai-Tong Wong
Keyword(s):  
Dna Repair ◽  
Therapeutic Strategy ◽  
Target Genes ◽  
Rna Seq ◽  
Downstream Target ◽  
Rb Phosphorylation ◽  
Glial Lineage

Abstract BACKGROUND Glial-lineage tumors constitute a heterogeneous group of neoplasms, comprising gliomas, oligodendrogliomas, and ependymomas, which account for 40%–50% of all pediatric central nervous system tumors. Advances in modern neuro-oncological therapeutics are aimed at improving neoadjuvant chemotherapy and deferring radiotherapy because radiation exposure may cause long-term side effects on the developing brain in young children. Despite aggressive treatment, more than half the high-grade gliomas (pHGGs) and one-third of ependymomas exhibit recurrence within 2 years of initial treatment. METHODS By using integrated bioinformatics and through experimental validation, we found that at least one gene among CCND1, CDK4, and CDK6 was overexpressed in pHGGs and ependymomas. RESULTS The use of abemaciclib, a highly selective CDK4/6 inhibitor, effectively inhibited cell proliferation and reduced the expression of cell cycle–related and DNA repair–related gene expression, which was determined through RNA-seq analysis. The efficiency of abemaciclib was validated in vitro in pHGGs and ependymoma cells and in vivo by using subcutaneously implanted ependymoma cells from patient-derived xenograft (PDX) in mouse models. Abemaciclib demonstrated the suppression of RB phosphorylation, downstream target genes of E2F, G2M checkpoint, and DNA repair, resulting in tumor suppression. CONCLUSION Abemaciclib showed encouraging results in preclinical pediatric glial-lineage tumors models and represented a potential therapeutic strategy for treating challenging tumors in children.

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