scholarly journals Feedback control of the Gpr161-Gαs-PKA axis contributes to basal Hedgehog repression in zebrafish

Development ◽  
2021 ◽  
Vol 148 (4) ◽  
pp. dev192443
Author(s):  
Philipp M. Tschaikner ◽  
Dominik Regele ◽  
Ruth Röck ◽  
Willi Salvenmoser ◽  
Dirk Meyer ◽  
...  
Keyword(s):  
Target Gene ◽  
Target Genes ◽  
Negative Regulator ◽  
Fine Tuning ◽  
Direct Patterning ◽  
Anchoring Protein ◽  
Increased Sensitivity ◽  
High Level ◽  
Inappropriate Expression ◽  
G Protein Coupled

ABSTRACTHedgehog (Hh) ligands act as morphogens to direct patterning and proliferation during embryonic development. Protein kinase A (PKA) is a central negative regulator of Hh signalling, and in the absence of Hh ligands, PKA activity prevents inappropriate expression of Hh target genes. The orphan G-protein-coupled receptor Gpr161 contributes to the basal Hh repression machinery by activating PKA. Gpr161 acts as an A-kinase-anchoring protein, and is itself phosphorylated by PKA, but the functional significance of PKA phosphorylation of Gpr161 in the context of Hh signalling remains unknown. Here, we show that loss of Gpr161 in zebrafish leads to constitutive activation of medium and low, but not maximal, levels of Hh target gene expression. Furthermore, we find that PKA phosphorylation-deficient forms of Gpr161, which we show directly couple to Gαs, display an increased sensitivity to Shh, resulting in excess high-level Hh signalling. Our results suggest that PKA feedback-mediated phosphorylation of Gpr161 may provide a mechanism for fine-tuning Gpr161 ciliary localisation and PKA activity.

scholarly journals Zebrafish GPR161 Contributes to Basal Hedgehog Repression in a Tissue-specific Manner

2019 ◽  
Author(s):  
Philipp Tschaikner ◽  
Dominik Regele ◽  
Willi Salvenmoser ◽  
Stephan Geley ◽  
Eduard Stefan ◽  
...  
Keyword(s):  
Target Gene ◽  
Target Genes ◽  
Negative Regulator ◽  
Fine Tuning ◽  
Tissue Specific ◽  
Relative Contribution ◽  
Direct Patterning ◽  
High Level ◽  
Inappropriate Expression ◽  
G Protein Coupled

AbstractHedgehog (Hh) ligands act as morphogens to direct patterning and proliferation during embryonic development. Protein kinase A (PKA) is a central negative regulator of Hh signalling, and in the absence of Hh ligands, PKA activity prevents inappropriate expression of Hh target genes. The Gαs- coupled receptor Gpr161 contributes to the basal Hh repression machinery by activating PKA, although the extent of this contribution is unclear. Here we show that loss of Gpr161 in zebrafish leads to constitutive activation of low-, but not high-level Hh target gene expression in the neural tube. In contrast, in the myotome, both high- and low-level Hh signalling is constitutively activated in the absence of Gpr161 function. Our results suggest that the relative contribution of Gpr161 to basal repression of Hh signalling is tissue-specific. Distinct combinations of G-protein-coupled receptors may allow the fine-tuning of PKA activity to ensure the appropriate sensitivity to Hh across different tissues.

The role of brinker in mediating the graded response to Dpp in early Drosophila embryos

Development ◽  
1999 ◽  
Vol 126 (15) ◽  
pp. 3323-3334 ◽  
Author(s):  
A. Jazwinska ◽  
C. Rushlow ◽  
S. Roth
Keyword(s):  
Target Gene ◽  
Target Genes ◽  
Gene Activation ◽  
Ectopic Expression ◽  
Intermediate Level ◽  
Graded Response ◽  
High Level ◽  
Drosophila Embryos ◽  
Novel Protein

Brinker (Brk), a novel protein with features of a transcriptional repressor, regulates the graded response to Decapentaplegic (Dpp) in appendage primordia of Drosophila. Here, we show that in the embryo brk also has differential effects on Dpp target genes, depending on the level of Dpp activity required for their activation. Low-level target genes, like dpp itself, tolloid and early zerknullt, show strong ectopic expression in ventrolateral regions of brk mutant embryos; intermediate-level target genes like pannier show weak ectopic expression, while high-level target genes like u-shaped and rhomboid are not affected. Ectopic target gene activation in the absence of brk is independent of Dpp, Tkv and Medea, indicating that Dpp signaling normally antagonizes brk's repression of these target genes. brk is expressed like short gastrulation (sog) in ventrolateral regions of the embryo abutting the dpp domain. Here, both brk and sog antagonize the antineurogenic activity of Dpp so that only in brk sog double mutants is the neuroectoderm completely deleted.

scholarly journals EP300 and SIRT1/6 Co-Regulate Lapatinib Sensitivity Via Modulating FOXO3-Acetylation and Activity in Breast Cancer

Cancers ◽  
2019 ◽  
Vol 11 (8) ◽  
pp. 1067 ◽  
Author(s):  
Zimam Mahmud ◽  
Ana R. Gomes ◽  
Hee Jin Lee ◽  
Sathid Aimjongjun ◽  
Yannasittha Jiramongkol ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Target Gene ◽  
Target Genes ◽  
Ectopic Expression ◽  
Sirtuin 1 ◽  
Fine Tuning ◽  
Gene Promoters ◽  
Breast Cancers ◽  
Her2 Positive ◽  
Cancer Subtypes

Forkhead Box O3 (FOXO3) is a tumor suppressor whose activity is fine-tuned by post-translational modifications (PTMs). In this study, using the BT474 breast cancer cells and a recently established lapatinib resistant (BT474-LapR) cell line, we observed that higher FOXO3 and acetylated (Ac)-FOXO3 levels correlate with lapatinib sensitivity. Subsequent ectopic expression of EP300 led to an increase in acetylated-FOXO3 in sensitive but not in resistant cells. Drug sensitivity assays revealed that sensitive BT474 cells show increased lapatinib cytotoxicity upon over-expression of wild-type but not acetylation-deficient EP300. Moreover, FOXO3 recruitment to target gene promoters is associated with target gene expression and drug response in sensitive cells and the inability of FOXO3 to bind its target genes correlates with lapatinib-resistance in BT474-LapR cells. In addition, using SIRT1/6 specific siRNAs and chemical inhibitor, we also found that sirtuin 1 and -6 (SIRT1 and -6) play a part in fine-tuning FOXO3 acetylation and lapatinib sensitivity. Consistent with this, immunohistochemistry results from different breast cancer subtypes showed that high SIRT6/1 levels are associated with constitutive high FOXO3 expression which is related to FOXO3 deregulation/inactivation and poor prognosis in breast cancer patient samples. Collectively, our results suggest the involvement of FOXO3 acetylation in regulating lapatinib sensitivity of HER2-positive breast cancers.

scholarly journals MiR-429 Determines Poor Outcome and Inhibits Pancreatic Ductal Adenocarcinoma Growth by Targeting TBK1

2015 ◽  
Vol 35 (5) ◽  
pp. 1846-1856 ◽  
Author(s):  
Bin Song ◽  
Kailian Zheng ◽  
Hongyun Ma ◽  
Anan Liu ◽  
Wei Jing ◽  
...  
Keyword(s):  
Pancreatic Ductal Adenocarcinoma ◽  
Cell Lines ◽  
Target Gene ◽  
Target Genes ◽  
Ductal Adenocarcinoma ◽  
Direct Target Gene ◽  
Direct Target ◽  
Sw1990 Cell ◽  
High Level

Background: Pancreatic ductal adenocarcinoma (PDAC) ranks fourth on the list of cancer-related causes of death and its prognosis has not improved significantly over the past decades. Deregulation or dysfunction of miRNAs contribute to cancer development. Previous data indicates that miR-429 is involved in the pathogenesis of PDAC. However, the role of miR-429 in PDAC remained unknown. Methods: MiR-429 levels in sample tissues of 78 patients and in PANC1 and SW1990 cell lines were quantified by real-time PCR. MiR-429 expression was modulated using specific pre- and anti-miRNAs and cell growth was assayed by MTT analysis. Bioinformatics prediction of the miR-429 putative target genes was performed and luciferase assays confirmed TBK1 as a direct target gene. TBK1 levels in PDAC tissues were analyzed by immunohistochemistry. Results: MiR-429 was remarkably decreased in PDAC tissues and cell lines. Lower miR-429 expression in PDAC tissues significantly correlated with shorter survival of PDAC patients. Overexpression of miR-429 inhibited PDAC cell lines growth in vitro and vice versa. TBK1 was found to be the direct target gene of miR-429. Higher TBK1 protein level in PDAC tissues correlated with shorter survival of PDAC patients. Overexpression of TBK1 partly restored cell proliferation. Conclusions: Low level of miR-429 and high level of TBK1 in PDAC promoted PDAC cells growth which might be related to the low survival rate of PDAC patients. MiR-429 play its role in PDAC by targeting TBK1.

scholarly journals RLP, a novel Ras-like protein, is an immediate-early transforming growth factor-β (TGF-β) target gene that negatively regulates transcriptional activity induced by TGF-β

2004 ◽  
Vol 383 (1) ◽  
pp. 187-199 ◽  
Author(s):  
Ester PIEK ◽  
Maarten van DINTHER ◽  
W. Tony PARKS ◽  
John M. SALLEE ◽  
Erwin P. BÖTTINGER ◽  
...  
Keyword(s):  
Growth Factor ◽  
Target Gene ◽  
Target Genes ◽  
Transforming Growth Factor ◽  
Transforming Growth Factor Β ◽  
Small Gtpases ◽  
Negative Regulator ◽  
Immediate Early ◽  
Ras Superfamily ◽  
Β Receptor

We have described previously the use of microarray technology to identify novel target genes of TGF-β (transforming growth factor-β) signalling in mouse embryo fibroblasts deficient in Smad2 or Smad3 [Yang, Piek, Zavadil, Liang, Xie, Heyer, Pavlidis, Kucherlapati, Roberts and Böttinger (2003) Proc. Natl. Acad. Sci. U.S.A. 100, 10269–10274]. Among the TGF-β target genes identified, a novel gene with sequence homology to members of the Ras superfamily was identified, which we have designated as RLP (Ras-like protein). RLP is a Smad3-dependent immediate-early TGF-β target gene, its expression being induced within 45 min. Bone morphogenetic proteins also induce expression of RLP, whereas epidermal growth factor and phorbol ester PMA suppress TGF-β-induced expression of RLP. Northern-blot analysis revealed that RLP was strongly expressed in heart, brain and kidney, and below the detection level in spleen and skeletal muscles. At the protein level, RLP is approx. 30% homologous with members of the Ras superfamily, particularly in domains characteristic for small GTPases. However, compared with prototypic Ras, RLP contains a modified P-loop, lacks the consensus G2 loop and the C-terminal prenylation site and harbours amino acid substitutions at positions that render prototypic Ras oncogenic. However, RLP does not have transforming activity, does not affect phosphorylation of mitogen-activated protein kinase and is unable to bind GTP or GDP. RLP was found to associate with certain subtypes of the TGF-β receptor family, raising the possibility that RLP plays a role in TGF-β signal transduction. Although RLP did not interact with Smads and did not affect TGF-β receptor-induced Smad2 phosphorylation, it inhibited TGF-β-induced transcriptional reporter activation, suggesting that it is a novel negative regulator of TGF-β signalling.

scholarly journals A ribosome assembly stress response regulates transcription to maintain proteome homeostasis

eLife ◽  
2019 ◽  
Vol 8 ◽  
Author(s):  
Benjamin Albert ◽  
Isabelle C Kos-Braun ◽  
Anthony K Henras ◽  
Christophe Dez ◽  
Maria Paula Rueda ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Ribosome Biogenesis ◽  
Target Genes ◽  
Insoluble Fraction ◽  
Negative Regulator ◽  
Ribosome Assembly ◽  
Gene Promoters ◽  
Yeast Saccharomyces Cerevisiae ◽  
Proteotoxic Stress ◽  
High Level

Ribosome biogenesis is a complex and energy-demanding process requiring tight coordination of ribosomal RNA (rRNA) and ribosomal protein (RP) production. Given the extremely high level of RP synthesis in rapidly growing cells, alteration of any step in the ribosome assembly process may impact growth by leading to proteotoxic stress. Although the transcription factor Hsf1 has emerged as a central regulator of proteostasis, how its activity is coordinated with ribosome biogenesis is unknown. Here, we show that arrest of ribosome biogenesis in the budding yeast Saccharomyces cerevisiae triggers rapid activation of a highly specific stress pathway that coordinately upregulates Hsf1 target genes and downregulates RP genes. Activation of Hsf1 target genes requires neo-synthesis of RPs, which accumulate in an insoluble fraction and presumably titrate a negative regulator of Hsf1, the Hsp70 chaperone. RP aggregation is also coincident with that of the RP gene activator Ifh1, a transcription factor that is rapidly released from RP gene promoters. Our data support a model in which the levels of newly synthetized RPs, imported into the nucleus but not yet assembled into ribosomes, work to continuously balance Hsf1 and Ifh1 activity, thus guarding against proteotoxic stress during ribosome assembly.

scholarly journals Target Gene-Specific Modulation of Myocardin Activity by GATA Transcription Factors

2004 ◽  
Vol 24 (19) ◽  
pp. 8519-8528 ◽  
Author(s):  
Jiyeon Oh ◽  
Zhigao Wang ◽  
Da-Zhi Wang ◽  
Ching-Ling Lien ◽  
Weibing Xing ◽  
...  
Keyword(s):  
Transcription Factors ◽  
Target Gene ◽  
Target Genes ◽  
Serum Response Factor ◽  
Fine Tuning ◽  
Physical Interaction ◽  
Response Factor ◽  
Muscle Gene Expression ◽  
Gata Transcription Factors ◽  
Serum Response

ABSTRACT Myocardin is a transcriptional coactivator that regulates cardiac and smooth muscle gene expression by associating with serum response factor. We show that GATA transcription factors can either stimulate or suppress the transcriptional activity of myocardin, depending on the target gene. Modulation of myocardin activity by GATA4 is mediated by the physical interaction of myocardin with the DNA binding domain of GATA4 but does not require binding of GATA4 to DNA. Paradoxically, the transcription activation domain of GATA4 is dispensable for the stimulatory effect of GATA4 on myocardin activity but is required for repression of myocardin activity. The ability of GATA transcription factors to modulate myocardin activity provides a potential mechanism for fine tuning the expression of serum response factor target genes in a gene-specific manner.

Bioinformatics Analysis and Validation of Differentially Expressed MicroRNAs with Their Target Genes Involved in GLP-1RA Facilitated Osteogenesis

2020 ◽  
Vol 15 ◽  
Author(s):  
Na Wang ◽  
Yukun Li ◽  
Sijing Liu ◽  
Liu Gao ◽  
Chang Liu ◽  
...  
Keyword(s):  
High Throughput Sequencing ◽  
Target Genes ◽  
Bioinformatics Analysis ◽  
Differentially Expressed ◽  
Functional Study ◽  
Regulation Network ◽  
Glucagon Like Peptide 1 ◽  
G Protein Coupled ◽  
Lower Expression

Background: Recent studies revealed that the hypoglycemic hormone, glucagon-like peptide-1 (GLP-1), acted as an important modulator in osteogenesis of bone marrow derived mesenchymal stem cells (BMSCs). Objectives: The aim of this study was to identify the specific microRNA (miRNA) using bioinformatics analysis and validate the presence of differentially expressed microRNAs with their target genes after GLP-1 receptor agonist (GLP-1RA) administration involved in ostogenesis of BMSCs. Methods: MiRNAs were extracted from BMSCs after 5 days’ treatment and sent for high-throughput sequencing for differentially expressed (DE) miRNAs analyses. Then the expression of the DE miRNAs verified by the real-time RT-PCR analyses. Target genes were predicted, and highly enriched GOs and KEGG pathway analysis were conducted using bioinformatics analysis. For the functional study, two of the target genes, SRY (sex determining region Y)-box 5 (SOX5) and G protein-coupled receptor 84 (GPR84), were identified. Results: A total of 5 miRNAs (miRNA-509-5p, miRNA-547-3p, miRNA-201-3p, miRNA-201-5p, and miRNA-novel-272-mature) were identified differentially expressed among groups. The expression of miRNA-novel-272-mature were decreased during the osteogenic differentiation of BMSCs, and GLP-1RA further decreased its expression. MiRNA-novel-272-mature might interact with its target mRNAs to enhance osteogenesis. The lower expression of miRNA-novel-272-mature led to an increase in SOX5 and a decrease in GPR84 mRNA expression, respectively. Conclusions: Taken together, these results provide further insights to the pharmacological properties of GLP-1RA and expand our knowledge on the role of miRNAs-mRNAs regulation network in BMSCs’ differentiation.

Artificial microRNA (amiRNA) induced gene silencing in alfalfa (Medicago sativa)

Botany ◽  
2013 ◽  
Vol 91 (2) ◽  
pp. 117-122 ◽  
Author(s):  
Julian C. Verdonk ◽  
Michael L. Sullivan
Keyword(s):  
Gene Silencing ◽  
Medicago Sativa ◽  
Target Gene ◽  
Target Genes ◽  
Mirna Precursor ◽  
Crop Species ◽  
Forage Crop ◽  
Ribonucleic Acids ◽  
Endogenous Gene ◽  
Medicago Sativa L

Gene silencing is a powerful technique that allows the study of the function of specific genes by selectively reducing their transcription. Several different approaches can be used, however they all have in common the artificial generation of single stranded small ribonucleic acids (RNAs) that are utilized by the endogenous gene silencing machinery of the organism. Artificial microRNAs (amiRNA) can be used to very specifically target genes for silencing because only a short sequence of 21 nucleotides of the gene of interest is used. Gene silencing via amiRNA has been developed for Arabidopsis thaliana (L.) Heynh. and rice using endogenous microRNA (miRNA) precursors and has been shown to also work effectively in other dicot species using the arabidopsis miRNA precursor. Here, we demonstrate that the arabidopsis miR319 precursor can be used to silence genes in the important forage crop species alfalfa (Medicago sativa L.) by silencing the expression of a transgenic beta-glucuronidase (GUSPlus) target gene.

scholarly journals CHOP-Dependent Stress-Inducible Expression of a Novel Form of Carbonic Anhydrase VI

1999 ◽  
Vol 19 (1) ◽  
pp. 495-504 ◽  
Author(s):  
John Sok ◽  
Xiao-Zhong Wang ◽  
Nikoleta Batchvarova ◽  
Masahiko Kuroda ◽  
Heather Harding ◽  
...  
Keyword(s):  
Carbonic Anhydrase ◽  
Target Gene ◽  
Target Genes ◽  
Direct Evidence ◽  
Nuclear Protein ◽  
Intracellular Form ◽  
Carbonic Anhydrase Vi ◽  
Responsive Element

ABSTRACT CHOP (also called GADD153) is a stress-inducible nuclear protein that dimerizes with members of the C/EBP family of transcription factors and was initially identified as an inhibitor of C/EBP binding to classic C/EBP target genes. Subsequent experiments suggested a role for CHOP-C/EBP heterodimers in positively regulating gene expression; however, direct evidence that this is the case has so far not been uncovered. Here we describe the identification of a positively regulated direct CHOP-C/EBP target gene, that encoding murine carbonic anhydrase VI (CA-VI). The stress-inducible form of the gene is expressed from an internal promoter and encodes a novel intracellular form of what is normally a secreted protein. Stress-induced expression of CA-VI is both CHOP and C/EBPβ dependent in that it does not occur in cells deficient in either gene. A CHOP-responsive element was mapped to the inducibleCA-VI promoter, and in vitro footprinting revealed binding of CHOP-C/EBP heterodimers to that site. Rescue of CA-VIexpression in c/ebpβ−/− cells by exogenous C/EBPβ and a shorter, normally inhibitory isoform of the protein known as LIP suggests that the role of the C/EBP partner is limited to targeting the CHOP-containing heterodimer to the response element and points to a preeminent role for CHOP in CA-VI induction during stress.

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