Hematopoietic induction and respecification of A-P identity by visceral endoderm signaling in the mouse embryo

Development ◽  
1998 ◽  
Vol 125 (24) ◽  
pp. 5009-5018 ◽  
Author(s):  
M. Belaoussoff ◽  
S.M. Farrington ◽  
M.H. Baron
Keyword(s):  
Mouse Embryo ◽  
Decisive Role ◽  
Primitive Streak ◽  
Explant Culture ◽  
Cell Contact ◽  
Primitive Endoderm ◽  
Cell Fates ◽  
Posterior Aspect ◽  
Anterior Posterior

The anteroposterior axis of the developing embryo becomes morphologically apparent at the onset of gastrulation with the formation of the primitive streak. This structure, where the first mesodermal cells arise, marks the posterior aspect of the embryo. To examine the potential role of non-mesodermal signals in specifying posterior (hematopoietic and endothelial) cell fates in the mouse embryo, we have devised a transgenic explant culture system. We show that interactions between primitive endoderm and adjacent embryonic ectoderm or nascent mesoderm are required early in gastrulation for initiation of hematopoiesis and vasculogenesis. Surprisingly, primitive endoderm signals can respecify anterior (prospective neural) ectoderm to a posterior mesodermal fate, resulting in formation of blood and activation of endothelial markers. Reprogramming of anterior ectoderm does not require cell contact and is effected by stage-dependent, short-range, diffusible signal(s). Therefore, primitive endoderm signaling is a critical early determinant of hematopoietic and vascular development and plays a decisive role in anterior-posterior patterning during mouse embryogenesis.

Anterior mesendoderm induces mouse Engrailed genes in explant cultures

Development ◽  
1993 ◽  
Vol 118 (1) ◽  
pp. 139-149 ◽  
Author(s):  
S.L. Ang ◽  
J. Rossant
Keyword(s):  
Direct Evidence ◽  
Neural Tissue ◽  
Explant Culture ◽  
Neural Plate ◽  
Explant Cultures ◽  
Neural Marker ◽  
Engrailed Genes ◽  
Anterior Posterior

We have developed germ layer explant culture assays to study the role of mesoderm in anterior-posterior (A-P) patterning of the mouse neural plate. Using isolated explants of ectodermal tissue alone, we have demonstrated that the expression of Engrailed-1 (En-1) and En-2 genes in ectoderm is independent of mesoderm by the mid- to late streak stage, at least 12 hours before their onset of expression in the neural tube in vivo at the early somite stage. In recombination explants, anterior mesendoderm from headfold stage embryos induces the expression of En-1 and En-2 in pre- to early streak ectoderm and in posterior ectoderm from headfold stage embryos. In contrast, posterior mesendoderm from embryos of the same stage does not induce En genes in pre- to early streak ectoderm but is able to induce expression of a general neural marker, neurofilament 160 × 10(3) M(r). These results provide the first direct evidence for a role of mesendoderm in induction and regionalization of neural tissue in mouse.

scholarly journals Role of Cell Contact in Compaction during the Third Cell Cycle of the Mouse Embryo.

1995 ◽  
Vol 12 (2) ◽  
pp. 85-93 ◽  
Author(s):  
Hidehiko Ogawa ◽  
Tadashi Mori ◽  
Hiroshi Shimizu
Keyword(s):  
Cell Cycle ◽  
Mouse Embryo ◽  
Cell Contact ◽  
The Third

Misexpression of Cwnt8C in the mouse induces an ectopic embryonic axis and causes a truncation of the anterior neuroectoderm

Development ◽  
1997 ◽  
Vol 124 (15) ◽  
pp. 2997-3005 ◽  
Author(s):  
H. Popperl ◽  
C. Schmidt ◽  
V. Wilson ◽  
C.R. Hume ◽  
J. Dodd ◽  
...  
Keyword(s):  
Mouse Embryo ◽  
Primitive Streak ◽  
Primitive Endoderm ◽  
Morphological Examination ◽  
Expression Domain ◽  
Anterior Aspect ◽  
Beta Actin ◽  
Early Expression ◽  
Actin Promoter ◽  
Transgenic Embryos

Transgenic embryos expressing Cwnt8C under the control of the human beta-actin promoter exhibit duplicated axes or a severely dorsalised phenotype. Although the transgene was introduced into fertilised eggs all duplications occurred within a single amnion and, therefore, arose from the production of more than one primitive streak at the time of gastrulation. Morphological examination and the expression of diagnostic markers in transgenic embryos suggested that ectopic Cwnt8C expression produced only incomplete axis duplication: axes were always fused anteriorly, there was a reduction in tissue rostral to the anterior limit of the notochord, and no duplicated expression domain of the forebrain marker Hesx1 was observed. Anterior truncations were evident in dorsalised transgenic embryos containing a single axis. These results are discussed in the light of the effects of ectopic Xwnt8 in Xenopus embryos, where its early expression leads to complete axis duplication but expression after the mid-blastula transition causes anterior truncation. It is proposed that while ectopic Cwnt8C in the mouse embryo can duplicate the primitive streak and node this only produces incomplete axis duplication because specification of the anterior aspect of the axis, as opposed to maintenance of anterior character, is established by interaction with anterior primitive endoderm rather than primitive streak derivatives.

HNF3beta and Lim1 interact in the visceral endoderm to regulate primitive streak formation and anterior-posterior polarity in the mouse embryo

Development ◽  
1999 ◽  
Vol 126 (20) ◽  
pp. 4499-4511 ◽  
Author(s):  
A. Perea-Gomez ◽  
W. Shawlot ◽  
H. Sasaki ◽  
R.R. Behringer ◽  
S. Ang
Keyword(s):  
Mouse Embryo ◽  
Primitive Streak ◽  
Axis Formation ◽  
Visceral Endoderm ◽  
Primary Defect ◽  
Homozygous Mutant ◽  
Early Mouse ◽  
Mesoderm Patterning ◽  
Anterior Posterior ◽  
Anterior Visceral Endoderm

Recent embryological and genetic experiments have suggested that the anterior visceral endoderm and the anterior primitive streak of the early mouse gastrula function as head- and trunk-organising centers, respectively. Here, we report that HNF3beta and Lim1 are coexpressed in both organising centers suggesting synergistic roles of these genes in regulating organiser functions and hence axis development in the mouse embryo. To investigate this possibility, we generated compound HNF3beta and Lim1 mutant embryos. An enlarged primitive streak and a lack of axis formation were observed in HNF3beta (−)(/)(−);Lim1(−)(/)(−), but not in single homozygous mutant embryos. Chimera experiments indicate that the primary defect in these double homozygous mutants is due to loss of activity of HNF3beta and Lim1 in the visceral endoderm. Altogether, these data provide evidence that these genes function synergistically to regulate organiser activity of the anterior visceral endoderm. Moreover, HNF3beta (−)(/)(−);Lim1(−)(/)(−) mutant embryos also exhibit defects in mesoderm patterning that are likely due to lack of specification of anterior primitive streak cells.

scholarly journals Control of early anterior-posterior patterning in the mouse embryo by TGF-β signalling

2003 ◽  
Vol 358 (1436) ◽  
pp. 1351-1358 ◽  
Author(s):  
Elizabeth J. Robertson ◽  
Dominic P. Norris ◽  
Jane Brennan ◽  
Elizabeth K. Bikoff
Keyword(s):  
Mouse Embryo ◽  
Transforming Growth Factor ◽  
Organizer Region ◽  
Primitive Streak ◽  
Transforming Growth Factor Β ◽  
Axis Formation ◽  
Posterior Side ◽  
Molecular Pattern ◽  
Discrete Population ◽  
Anterior Posterior

Prior to gastrulation the mouse embryo exists as a symmetrical cylinder consisting of three tissue layers. Positioning of the future anterior–posterior axis of the embryo occurs through coordinated cell movements that rotate a pre–existing proximal–distal (P–D) axis. Overt axis formation becomes evident when a discrete population of proximal epiblast cells become induced to form mesoderm, initiating primitive streak formation and marking the posterior side of the embryo. Over the next 12–24 h the primitive streak gradually elongates along the posterior side of the epiblast to reach the distal tip. The most anterior streak cells comprise the ‘organizer’ region and include the precursors of the so–called ‘axial mesendoderm’, namely the anterior definitive endoderm and prechordal plate mesoderm, as well as those cells that give rise to the morphologically patent node. Signalling pathways controlled by the transforming growth factor–β ligand nodal are involved in orchestrating the process of axis formation. Embryos lacking nodal activity arrest development before gastrulation, reflecting an essential role for nodal in establishing P–D polarity by generating and maintaining the molecular pattern within the epiblast, extraembryonic ectoderm and the visceral endoderm. Using a genetic strategy to manipulate temporal and spatial domains of nodal expression reveals that the nodal pathway is also instrumental in controlling both the morphogenetic movements required for orientation of the final axis and for specification of the axial mesendoderm progenitors.

scholarly journals The role of Pten in anterior–posterior (AP) axis formation in the mouse embryo

2008 ◽  
Vol 319 (2) ◽  
pp. 584
Author(s):  
Joshua E. Bloomekatz ◽  
Andrew Rakeman ◽  
Heather Alcorn ◽  
Kathryn V. Anderson
Keyword(s):  
Mouse Embryo ◽  
Axis Formation ◽  
Anterior Posterior

scholarly journals Antagonism between Smad1 and Smad2 signaling determines the site of distal visceral endoderm formation in the mouse embryo

2009 ◽  
Vol 184 (2) ◽  
pp. 323-334 ◽  
Author(s):  
Masamichi Yamamoto ◽  
Hideyuki Beppu ◽  
Katsuyoshi Takaoka ◽  
Chikara Meno ◽  
En Li ◽  
...  
Keyword(s):  
Mouse Embryo ◽  
Early Stage ◽  
Distal Region ◽  
Bmp Signaling ◽  
Visceral Endoderm ◽  
Inverse Relation ◽  
Primitive Endoderm ◽  
Dual Roles ◽  
Morphogenetic Protein ◽  
Anterior Posterior

The anterior–posterior axis of the mouse embryo is established by formation of distal visceral endoderm (DVE) and its subsequent migration. The precise mechanism of DVE formation has remained unknown, however. Here we show that bone morphogenetic protein (BMP) signaling plays dual roles in DVE formation. BMP signaling is required at an early stage for differentiation of the primitive endoderm into the embryonic visceral endoderm (VE), whereas it inhibits DVE formation, restricting it to the distal region, at a later stage. A Smad2-activating factor such as Activin also contributes to DVE formation by generating a region of VE positive for the Smad2 signal and negative for Smad1 signal. DVE is thus formed at the distal end of the embryo, the only region of VE negative for the Smad1 signal and positive for Smad2 signal. An inverse relation between the level of phosphorylated Smad1 and that of phosphorylated Smad2 in VE suggests an involvement of antagonism between Smad1- and Smad2-mediated signaling.

scholarly journals Mapping cell migrations and fates from a gastruloid model to the human primitive streak

2019 ◽  
Author(s):  
I. Martyn ◽  
E.D. Siggia ◽  
A.H. Brivanlou
Keyword(s):  
Mouse Embryo ◽  
Cell Tracking ◽  
Primitive Streak ◽  
Parallel Analysis ◽  
Self Organization ◽  
Model Organisms ◽  
Fate Map ◽  
Dependent Cell ◽  
Early Gastrula ◽  
Anterior Posterior

AbstractAlthough fate maps of early gastrula embryos exist for nearly all model organisms, a fate map of the gastrulating human embryo remains elusive. Here we use human gastruloids to piece together part of a rudimentary fate map of the human primitive streak (PS). This is possible because stimulation with differing levels of BMP, WNT, and NODAL leads to self-organization of gastruloids into large and homogenous different subpopulations of endoderm and mesoderm, and comparative parallel analysis of these gastruloids, together with the fate map of the mouse embryo, allows the organization of these subpopulations along an anterior-posterior axis. We also developed a novel cell tracking technique that allowed the detection of robust fate-dependent cell migrations in our gastruloids comparable to those found in the mouse embryo. Taken together, our gastruloid derived fate map and recording of cell migrations provides a first coarse view of the embryonic human PS.

Origin and role of distal visceral endoderm, a group of cells that determines anterior–posterior polarity of the mouse embryo

2011 ◽  
Vol 13 (7) ◽  
pp. 743-752 ◽  
Author(s):  
Katsuyoshi Takaoka ◽  
Masamichi Yamamoto ◽  
Hiroshi Hamada
Keyword(s):  
Mouse Embryo ◽  
Visceral Endoderm ◽  
Anterior Posterior
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