FGF-4 regulates expression of Evx-1 in the developing mouse limb

Development ◽  
1993 ◽  
Vol 119 (1) ◽  
pp. 287-294 ◽  
Author(s):  
L. Niswander ◽  
G.R. Martin

We describe here the temporal and spatial pattern of expression of Evx-1, a murine homolog of the Drosophila even-skipped gene, in the developing limb bud. Evx-1 RNA is first detected in distal limb (progress zone) mesenchyme shortly after the formation of the apical ectodermal ridge. The level of Evx-1 RNA increases during the next 24 hours of development, and then decreases in the subsequent 24 hours, such that by the time the ridge regresses Evx-1 RNA is undetectable. At all these stages, Evx-1 RNA is localized primarily to the posterior distal mesenchyme, in the region immediately underlying that portion of the ridge in which the Fgf-4 gene is expressed. Using an in vitro culture system, we show that the ridge is required for both the induction and maintenance of Evx-1 expression in the distal mesenchyme. We also demonstrate that in the absence of the ridge, FGF-4, as well as other FGF proteins, can induce Evx-1 expression in the limb bud. However, this effect appears to be indirect, since it can be blocked by an inhibitor of protein synthesis. Additional studies demonstrate that the effect of FGF-4 on Evx-1 expression is modulated by BMP-2. These data serve to identify Evx-1 as a downstream gene in the FGF signal transduction pathway in the limb.

1995 ◽  
Vol 130 (4) ◽  
pp. 997-1003 ◽  
Author(s):  
T Ochiya ◽  
H Sakamoto ◽  
M Tsukamoto ◽  
T Sugimura ◽  
M Terada

The initiation of limb development depends on the site specific proliferation of the mesenchyme by the signals from the apical ectodermal ridge (AER) in embryonic mouse. We have previously reported that the local expression of Hst-1/Fgf-4 transcripts in AER of the mouse limb bud is developmentally regulated, expressed at 11 and 12 days post coitus (p.c.) embryo. In an effort to further understand the role of Hst-1/FGF-4 in mouse limb development, an antisense oligodeoxynucleotides (ODNs) study was performed. We first established a novel organ culture system to study mouse limb development in vitro. This system allows mouse limb bud at 9.5-10-d p.c. embryo, when placed on a sheet of extracellular matrix in a defined medium, to differentiate into a limb at 12.5-d p.c. embryo within 4.5 d. Using this organ culture system, we have shown that exposure of 9.5-10-d p.c. embryonal limb bud explants to antisense ODNs of Hst-1/FGF-4 blocks limb development. In contrast, sense and scrambled ODNs have no inhibitory effect on limb outgrowth, suggesting that Hst-1/FGF-4 may work as a potent inducing factor for mouse limb development.


2014 ◽  
Vol 29 (4) ◽  
pp. 457-469 ◽  
Author(s):  
Federica Riva ◽  
Claudia Omes ◽  
Roberto Bassani ◽  
Rossella E Nappi ◽  
Giuliano Mazzini ◽  
...  

1991 ◽  
Vol 11 (12) ◽  
pp. 6016-6025
Author(s):  
X K Zhang ◽  
K N Wills ◽  
M Husmann ◽  
T Hermann ◽  
M Pfahl

Many essential biological pathways, including cell growth, development, and metabolism, are regulated by thyroid hormones (THs). TH action is mediated by intracellular receptors that belong to a large family of ligand-dependent transcription factors, including the steroid hormone and retinoic acid receptors. So far it has been assumed that TH receptors (TRs) regulate gene transcription only through the classical protein-DNA interaction mechanism. Here we provide evidence for a regulatory pathway that allows cross-talk between TRs and the signal transduction pathway used by many growth factors, oncogenes, and tumor promoters. In transient transfection studies, we observed that the oncogenes c-jun and c-fos inhibit TR activities, while TRs inhibit induction of the c-fos promoter and repress AP-1 site-dependent gene activation. A truncated TR that lacks only 17 amino acids from the carboxy terminus can no longer antagonize AP-1 activity. The cross-regulation between TRs and the signal transduction pathway appears to be based on the ability of TRs to inhibit DNA binding of the transcription factor AP-1 in the presence of THs. The constituents of AP-1, c-Jun, and c-Fos, vice versa, can inhibit TR-induced gene activation in vivo, and c-Jun inhibits TR DNA binding in vitro. This novel regulatory pathway is likely to play a major role in growth control and differentiation by THs.


1993 ◽  
Vol 13 (9) ◽  
pp. 5659-5669 ◽  
Author(s):  
M Tyers ◽  
B Futcher

In the yeast Saccharomyces cerevisiae, the Cdc28 protein kinase controls commitment to cell division at Start, but no biologically relevant G1-phase substrates have been identified. We have studied the kinase complexes formed between Cdc28 and each of the G1 cyclins Cln1, Cln2, and Cln3. Each complex has a specific array of coprecipitated in vitro substrates. We identify one of these as Far1, a protein required for pheromone-induced arrest at Start. Treatment with alpha-factor induces a preferential association and/or phosphorylation of Far1 by the Cln1, Cln2, and Cln3 kinase complexes. This induced interaction depends upon the Fus3 protein kinase, a mitogen-activated protein kinase homolog that functions near the bottom of the alpha-factor signal transduction pathway. Thus, we trace a path through which a mitogen-activated protein kinase regulates a Cdc2 kinase.


2011 ◽  
Vol 40 (1) ◽  
pp. 124-128
Author(s):  
Sabine Wohlres-Viana ◽  
Mariana Cortes Boite ◽  
João Henrique Moreira Viana ◽  
Marco Antonio Machado ◽  
Luiz Sérgio de Almeida Camargo

The objectives of this work were to identify and to evaluate possible differences on gene expression of aquaporins and Na/K-ATPases transcripts between embryos in vivo and in vitro produced. For each group, 15 blastocysts distributed in three pools were used for RNA extraction followed by amplification and reverse transcription. The resulting cDNAs were submitted to Real-Time PCR, using the GAPDH gene as endogenous control. It was not possible to identify AQP1 transcripts. Relative expression of AQP3 (1.33 ± 0.78) and AQP11 (2.00 ± 1.42) were not different in blastocysts in vitro and in vivo produced. Na/K-ATPase α1 gene (2.25 ± 1.07) was overregulated whereas Na/K-ATPase β2 transcripts 0.40 ± 0.30) did not differ among blastocysts produced in vitro from those produced in vivo. Transcripts for gene AQP1 are not present in bovine blastocysts. In vitro culture system does not alter expression of genes AQP3, AQP11 and Na/K-ATPase β2 genes, however, it affects expression of Na/K-ATPase α1.


2008 ◽  
Vol 12 (2) ◽  
pp. 64-70 ◽  
Author(s):  
Liren Tang ◽  
Mingwan Su ◽  
Yi Zhang ◽  
Wency Ip ◽  
Magdalena Martinka ◽  
...  

Background: Endothelin-3 (ET-3) is an essential paracrine factor for the proliferation, migration, and survival of embryonic melanocytes during fetal development. Its expression is tightly regulated, being completely turned off in adult skin. Objective: In this study, results are presented that demonstrate abnormal expression of ET-3 by metastatic melanoma cells in both tissue biopsies and cell culture. Further, in vitro experiments showed that metastatic melanoma cells have the capacity to respond to ET-3 stimulation by increasing survival. Conclusion: Therefore, an abnormal autocrine stimulation pathway involving ET-3 is present in metastatic melanoma cells. Blocking this signal transduction pathway may prove useful for the treatment of metastatic melanoma.


Blood ◽  
1997 ◽  
Vol 90 (2) ◽  
pp. 612-619 ◽  
Author(s):  
Matthias Ballmaier ◽  
Harald Schulze ◽  
Gabriele Strauβ ◽  
Klara Cherkaoui ◽  
Nicole Wittner ◽  
...  

The pathophysiology of thrombocytopenia in the syndrome of thrombocytopenia with absent radii (TAR) is not yet understood. We examined thrombopoietin (TPO) serum levels and the in vitro reactivity of platelets to TPO in five patients affected with TAR syndrome. We found elevated TPO serum levels in all patients tested, excluding a TPO production defect as cause for thrombocytopenia in TAR syndrome. In addition, we found similar expression of the TPO receptor c-Mpl on the surface of platelets from TAR patients (5 of 5) and a similar molecular weight of the receptor as compared with healthy controls (4 of 4). Platelet response to adenosine diphosphate or thrombin receptor agonist peptide SFLLRN (TRAP) was normal in TAR patients. However, in contrast to results with healthy controls we could show absence of in vitro reactivity of platelets from TAR patients to recombinant TPO as measured by testing TPO synergism to adenine diphosphate and TRAP in platelet activation. TPO induced tyrosine phosphorylation of platelet proteins was completely absent (3 of 4) or markedly decreased (1 of 4). Our results indicate that defective megakaryocytopoiesis/thrombocytopoiesis in TAR syndrome is not caused by a defect in TPO production but a lack of response to TPO in the signal transduction pathway of c-Mpl.


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