scholarly journals Barhl2 maintains T cell factors as repressors and thereby switches off the Wnt/β-Catenin response driving Spemann organizer formation

Development ◽  
2019 ◽  
Vol 146 (10) ◽  
pp. dev173112 ◽  
Author(s):  
Elena Sena ◽  
Nathalie Rocques ◽  
Caroline Borday ◽  
Harem Sabr Muhamad Amin ◽  
Karine Parain ◽  
...  
Keyword(s):  
T Cell ◽  
Spemann Organizer ◽  
Organizer Formation

scholarly journals Self-regulation of the head-inducing properties of the Spemann organizer

2012 ◽  
Vol 109 (38) ◽  
pp. 15354-15359 ◽  
Author(s):  
Masafumi Inui ◽  
Marco Montagner ◽  
Danny Ben-Zvi ◽  
Graziano Martello ◽  
Sandra Soligo ◽  
...  
Keyword(s):  
Growth Factors ◽  
Cross Talk ◽  
Self Regulation ◽  
Embryonic Patterning ◽  
Germ Layers ◽  
Limited Availability ◽  
Spemann Organizer ◽  
Qualitative Models ◽  
Organizer Formation

The Spemann organizer stands out from other signaling centers of the embryo because of its broad patterning effects. It defines development along the anteroposterior and dorsoventral axes of the vertebrate body, mainly by secreting antagonists of growth factors. Qualitative models proposed more than a decade ago explain the organizer’s region-specific inductions (i.e., head and trunk) as the result of different combinations of antagonists. For example, head induction is mediated by extracellular inhibition of Wnt, BMP, and Nodal ligands. However, little is known about how the levels of these antagonists become harmonized with those of their targets and with the factors initially responsible for germ layers and organizer formation, including Nodal itself. Here we show that key ingredients of the head-organizer development, namely Nodal ligands, Nodal antagonists, and ADMP ligands reciprocally adjust each other’s strength and range of activity by a self-regulating network of interlocked feedback and feedforward loops. A key element in this cross-talk is the limited availability of ACVR2a, for which Nodal and ADMP must compete. By trapping Nodal extracellularly, the Nodal antagonists Cerberus and Lefty are permissive for ADMP activity. The system self-regulates because ADMP/ACVR2a/Smad1 signaling in turn represses the expression of the Nodal antagonists, reestablishing the equilibrium. In sum, this work reveals an unprecedented set of interactions operating within the organizer that is critical for embryonic patterning.

scholarly journals Analysis of Spemann organizer formation in Xenopus embryos by cDNA macroarrays

2004 ◽  
Vol 269 (2) ◽  
pp. 552-566 ◽  
Author(s):  
Oliver Wessely ◽  
James I Kim ◽  
Douglas Geissert ◽  
Uyen Tran ◽  
E.M De Robertis
Keyword(s):  
Spemann Organizer ◽  
Xenopus Embryos ◽  
Cdna Macroarrays ◽  
Organizer Formation

Electron microscope study of the secretory activity of epithelial cells in embryonic thymus

1990 ◽  
Vol 48 (3) ◽  
pp. 382-383
Author(s):  
H. Alasam
Keyword(s):  
Cell Differentiation ◽  
T Cell ◽  
Epithelial Cells ◽  
Electron Density ◽  
Secretory Activity ◽  
T Cell Differentiation ◽  
High Electron ◽  
Transmission Electron ◽  
Medullary Epithelial Cells ◽  
Thymic Factor

The possibility that intrathymic T-cell differentiation involves stem cell-lymphoid interactions in embryos led us to study the ultrastructure of epithelial cell in normal embryonic thymus. Studies in adult thymus showed that it produces several peptides that induce T-cell differentiation. Several of them have been chemically characterized, such as thymosin α 1, thymopoietin, thymic humoral factor or the serum thymic factor. It was suggested that most of these factors are secreted by populations of A and B-epithelial cells.Embryonic materials were obtained from inbred matings of Swiss Albino mice. Thymuses were disected from embryos 17 days old and prepared for transmission electron microscopy. Our studies showed that embryonic thymus at this stage contains undifferentiated and differentiated epithelial cells, large lymphoblasts, medium and few small lymphocytes (Fig. 5). No differences were found between cortical and medullary epithelial cells, in contrast to the findings of Van Vliet et al,. Epithelial cells were mostly of the A-type with low electron density in both cytoplasm and nucleus. However few B-type with high electron density were also found (Fig. 7).

FAILURE TO DETECT ANTI-HTLV-1 ANTIBODY IN A PATIENT WITH ADULT T-CELL LEUKAEMIA/LYMPHOMA

1998 ◽  
Vol 103 (4) ◽  
pp. 1207-1208 ◽  
Author(s):  
Shan-Shun Luo ◽  
Hideto Tamura ◽  
Norio Yokose ◽  
Kiyoyuki Ogata ◽  
Kazuo Dan
Keyword(s):  
T Cell ◽  
Cell Leukaemia

Staging laparotomy in cutaneous T-cell disease

1981 ◽  
Vol 117 (9) ◽  
pp. 543-546 ◽  
Author(s):  
J. A. Doyle
Keyword(s):  
T Cell ◽  
Cell Disease ◽  
Staging Laparotomy

Herpes zoster-varicella in cutaneous T-cell lymphomas

1980 ◽  
Vol 116 (4) ◽  
pp. 408-412 ◽  
Author(s):  
E. C. Vonderheid
Keyword(s):  
Herpes Zoster ◽  
T Cell ◽  
T Cell Lymphomas
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