scholarly journals The RNA helicase DDX6 controls early mouse embryogenesis by repressing aberrant inhibition of BMP signaling through miRNA-mediated gene silencing

2021 ◽  
Author(s):  
Jessica Kim ◽  
Masafumi Muraoka ◽  
Rieko Ajima ◽  
Hajime Okada ◽  
Atsushi Toyoda ◽  
...  
Keyword(s):  
Cell Fate ◽  
Primitive Streak ◽  
Rna Helicase ◽  
Bmp Signaling ◽  
Negative Regulators ◽  
Pluripotent Cells ◽  
Mouse Embryogenesis ◽  
Neural Lineage ◽  
Early Mouse

The evolutionarily conserved RNA helicase DDX6 is a central player of post-transcriptional regulation, but its role during embryogenesis remains elusive. We here demonstrated that DDX6 enables proper cell lineage specification from pluripotent cells by analyzing Ddx6 KO mouse embryos and in vitro epiblast-like cell (EpiLC) induction system. Our study unveiled a great impact of DDX6-mediated RNA regulation on signaling pathways. Deletion of Ddx6 caused the aberrant transcriptional upregulation of the negative regulators of BMP signaling, which accompanied with enhanced Nodal signaling. Ddx6 / pluripotent cells acquired higher pluripotency with a strong inclination toward neural lineage commitment. During gastrulation, abnormally expanded Nodal expression in the primitive streak likely promoted endoderm cell fate specification while inhibiting mesoderm development. We further clarified the mechanism how DDX6 regulates cell fate determination of pluripotent cells by genetically dissecting major DDX6 pathways: processing body (P-body) formation, translational repression, mRNA decay, and miRNA-mediated silencing. P-body-related functions were dispensable, but the miRNA pathway was essential for the DDX6 function. DDX6 may prevent aberrant transcriptional upregulation of the negative regulators of BMP signaling by repressing translation of certain transcription factors through the interaction with miRNA-induced silencing complexes (miRISCs). Overall, this delineates how DDX6 affects development of the three primary germ layers during early mouse embryogenesis and the underlying mechanism of DDX6 function.

scholarly journals Mouse embryo geometry drives formation of robust signaling gradients through receptor localization

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Zhechun Zhang ◽  
Steven Zwick ◽  
Ethan Loew ◽  
Joshua S. Grimley ◽  
Sharad Ramanathan
Keyword(s):  
Cell Fate ◽  
Mouse Embryo ◽  
Basolateral Membrane ◽  
Embryonic Stem ◽  
Bmp Signaling ◽  
Receptor Localization ◽  
Bmp Receptors ◽  
Early Mouse

Abstract Morphogen signals are essential for cell fate specification during embryogenesis. Some receptors that sense these morphogens are known to localize to only the apical or basolateral membrane of polarized cell lines in vitro. How such localization affects morphogen sensing and patterning in the developing embryo remains unknown. Here, we show that the formation of a robust BMP signaling gradient in the early mouse embryo depends on the restricted, basolateral localization of BMP receptors. The mis-localization of receptors to the apical membrane results in ectopic BMP signaling in the mouse epiblast in vivo. With evidence from mathematical modeling, human embryonic stem cells in vitro, and mouse embryos in vivo, we find that the geometric compartmentalization of BMP receptors and ligands creates a signaling gradient that is buffered against fluctuations. Our results demonstrate the importance of receptor localization and embryo geometry in shaping morphogen signaling during embryogenesis.

scholarly journals Quantitative analysis of signaling responses during mouse primordial germ cell specification

Biology Open ◽  
2021 ◽  
Vol 10 (5) ◽  
Author(s):  
Sophie M. Morgani ◽  
Anna-Katerina Hadjantonakis
Keyword(s):  
Cell Fate ◽  
Primordial Germ Cells ◽  
Primordial Germ Cell ◽  
Small Population ◽  
Bmp Signaling ◽  
Pluripotent Cells ◽  
Cell Fate Decisions ◽  
Germ Cell Specification

ABSTRACT During early mammalian development, the pluripotent cells of the embryo are exposed to a combination of signals that drive exit from pluripotency and germ layer differentiation. At the same time, a small population of pluripotent cells give rise to the primordial germ cells (PGCs), the precursors of the sperm and egg, which pass on heritable genetic information to the next generation. Despite the importance of PGCs, it remains unclear how they are first segregated from the soma, and if this involves distinct responses to their signaling environment. To investigate this question, we mapped BMP, MAPK and WNT signaling responses over time in PGCs and their surrounding niche in vitro and in vivo at single-cell resolution. We showed that, in the mouse embryo, early PGCs exhibit lower BMP and MAPK responses compared to neighboring extraembryonic mesoderm cells, suggesting the emergence of distinct signaling regulatory mechanisms in the germline versus soma. In contrast, PGCs and somatic cells responded comparably to WNT, indicating that this signal alone is not sufficient to promote somatic differentiation. Finally, we investigated the requirement of a BMP response for these cell fate decisions. We found that cell lines with a mutation in the BMP receptor (Bmpr1a−/−), which exhibit an impaired BMP signaling response, can efficiently generate PGC-like cells revealing that canonical BMP signaling is not cell autonomously required to direct PGC-like differentiation.

scholarly journals Quantitative analysis of signaling responses during mouse primordial germ cell specification

2021 ◽  
Author(s):  
Sophie M. Morgani ◽  
Anna-Katerina Hadjantonakis
Keyword(s):  
Cell Fate ◽  
Primordial Germ Cells ◽  
Primordial Germ Cell ◽  
Small Population ◽  
Bmp Signaling ◽  
Pluripotent Cells ◽  
Cell Fate Decisions ◽  
Germ Cell Specification

AbstractDuring early mammalian development, the pluripotent cells of the embryo are exposed to a combination of signals that drive exit from pluripotency and germ layer differentiation. At the same time, a small population of pluripotent cells give rise to the primordial germ cells (PGCs), the precursors of the sperm and egg, which pass on heritable genetic information to the next generation. Despite the importance of PGCs, it remains unclear how they are first segregated from the soma, and if this involves distinct responses to their signaling environment. To investigate this question, we mapped BMP, MAPK and WNT signaling responses over time in PGCs and their surrounding niche in vitro and in vivo at single-cell resolution. We showed that, in the mouse embryo, early PGCs exhibit lower BMP and MAPK responses compared to neighboring extraembryonic mesoderm cells, suggesting the emergence of distinct signaling regulatory mechanisms in the germline versus soma. In contrast, PGCs and somatic cells responded comparably to WNT, indicating that this signal alone is not sufficient to promote somatic differentiation. Finally, we investigated the requirement of a BMP response for these cell fate decisions. We found that cell lines with a mutation in the BMP receptor (Bmpr1a−/−), which exhibit an impaired BMP signaling response, can efficiently generate PGC-like cells revealing that canonical BMP signaling is not cell autonomously required to direct PGC-like differentiation.

scholarly journals Embryo geometry drives formation of robust signaling gradients through receptor localization

2018 ◽  
Author(s):  
Zhechun Zhang ◽  
Steven Zwick ◽  
Ethan Loew ◽  
Joshua S Grimley ◽  
Sharad Ramanathan
Keyword(s):  
Cell Fate ◽  
Mouse Embryo ◽  
Basolateral Membrane ◽  
Bmp Signaling ◽  
Early Mouse Embryo ◽  
Receptor Localization ◽  
Bmp Receptors ◽  
Early Mouse ◽  
Embryonic Ectoderm

Morphogen signals are essential for cell fate specification during embryogenesis. Some receptors that sense these morphogen signals are known to localize to only the apical or basolateral membrane of polarized cell lines in vitro. How such localization affects morphogen sensing and patterning in the developing embryo remains unknown. Here, we show in the early mouse embryo that the formation of a robust BMP signaling gradient depends on restricted, basolateral localization of the BMP receptors. Mis-localizing these receptors to apical membrane leads to ectopic BMP signaling in the mouse embryo. To reach the basolaterally localized receptors in epiblast, BMP4 ligand, secreted by the extra-embryonic ectoderm, has to diffuses through the narrow interstitial space between the epiblast and the underlying endoderm. This restricted, basolateral diffusion creates a signaling gradient. The embryo geometry further buffers the gradient from fluctuations in the levels of BMP4. Our results demonstrate the importance of receptor localization and embryo geometry in shaping morphogen signaling during embryogenesis.

scholarly journals SyNPL: Synthetic Notch pluripotent cell lines to monitor and manipulate cell interactions in vitro and in vivo

2021 ◽  
Author(s):  
Mattias Malaguti ◽  
Rosa Portero Migueles ◽  
Jennifer Annoh ◽  
Daina Sadurska ◽  
Guillaume Blin ◽  
...  
Keyword(s):  
Cell Fate ◽  
Cell Lines ◽  
Modular Design ◽  
Cell Interactions ◽  
Cell Populations ◽  
Cell Contact ◽  
Pluripotent Cells ◽  
Cell Fate Decisions ◽  
Cell Cell

ABSTRACTCell-cell interactions govern differentiation and cell competition in pluripotent cells during early development, but the investigation of such processes is hindered by a lack of efficient analysis tools. Here we introduce SyNPL: clonal pluripotent stem cell lines which employ optimised Synthetic Notch (SynNotch) technology to report cell-cell interactions between engineered “sender” and “receiver” cells in cultured pluripotent cells and chimaeric mouse embryos. A modular design makes it straightforward to adapt the system for programming differentiation decisions non-cell-autonomously in receiver cells in response to direct contact with sender cells. We demonstrate the utility of this system by enforcing neuronal differentiation at the boundary between two cell populations. In summary, we provide a new tool which could be used to identify cell interactions and to profile changes in gene or protein expression that result from direct cell-cell contact with defined cell populations in culture and in early embryos, and which can be adapted to generate synthetic patterning of cell fate decisions.

scholarly journals Prediction and control of symmetry breaking in embryoid bodies by environment and signal integration

2018 ◽  
Author(s):  
Naor Sagy ◽  
Shaked Slovin ◽  
Maya Allalouf ◽  
Maayan Pour ◽  
Gaya Savyon ◽  
...  
Keyword(s):  
Symmetry Breaking ◽  
Cell Fate ◽  
Developmental Process ◽  
Primitive Streak ◽  
Early Embryo ◽  
Embryoid Bodies ◽  
Neighboring Cell ◽  
Contact Points

AbstractDuring early embryogenesis, mechanical signals, localized biochemical signals and neighboring cell layers interaction coordinate around anteroposterior axis determination and symmetry breaking. Deciphering their relative roles, which are hard to tease apart in vivo, will enhance our understanding of how these processes are driven. In recent years, in vitro 3D models of early mammalian development, such as embryoid bodies (EBs) and gastruloids, were successful in mimicking various aspects of the early embryo, providing high throughput accessible systems for studying the basic rules shaping cell fate and morphology during embryogenesis. Using Brachyury (Bry), a primitive streak and mesendoderm marker in EBs, we study how contact, biochemical and neighboring cell cues affect the positioning of a primitive streak-like locus, determining the AP axis. We show that a Bry-competent layer must be formed in the EB before Bry expression initiates, and that Bry onset locus selection depends on contact points of the EB with its surrounding. We can maneuver Bry onset to occur at a specific locus, a few loci, or in an isotropic peripheral pattern. By spatially separating contact and biochemical signal sources, we show these two modalities can be integrated by the EB to generate a single Bry locus. Finally, we show Foxa2+ cells are predictive of the future location of Bry onset, demonstrating an earlier symmetry-breaking event. By delineating the temporal signaling pathway dependencies of Bry and Foxa2, we were able to selectively abolish either, or spatially decouple the two cell types during EB differentiation. These findings demonstrate multiple inputs integration during an early developmental process, and may prove valuable in directing in vitro differentiation.

Influence of diandric and digynic triploid genotypes on early mouse embryogenesis

Development ◽  
1989 ◽  
Vol 105 (1) ◽  
pp. 137-145
Author(s):  
M.H. Kaufman ◽  
K.K. Lee ◽  
S. Speirs
Keyword(s):  
Embryonic Development ◽  
Primitive Streak ◽  
Stages Of Development ◽  
Mouse Embryogenesis ◽  
Somite Stage ◽  
Wide Range ◽  
Extraembryonic Membranes ◽  
Early Mouse ◽  
Hydatidiform Moles

Standard micromanipulatory techniques were used to produce tripronucleate diandric and digynic triploid mouse conceptuses. When these were transferred to suitable recipients, most implanted. A wide range of embryonic stages from the primitive streak to the 15- to 25-somite stage were isolated in both triploid series in otherwise identical recipients. In the diandric triploid series, all of the embryos recovered appeared to be morphologically normal, but considerably smaller than fertilized embryos analysed at similar stages of development. This contrasts with the digynic triploid conceptuses which, though also ranging from the primitive-streak stage to about the 10- to 15-somite stage at the time of their isolation, generally showed poorer embryonic development than the diandric triploids, and were invariably morphologically abnormal. Unlike the situation observed in man, where the placentas of diandric triploid conceptuses commonly display widespread trophoblastic hyperplasia and form the characteristic ‘partial’ or ‘incomplete’ type of hydatidiform moles, the extraembryonic membranes of the diandric triploid mouse conceptuses (as well as the digynic triploids) did not appear to be grossly abnormal).

Cell fate, morphogenetic movement and population kinetics of embryonic endoderm at the time of germ layer formation in the mouse

Development ◽  
1987 ◽  
Vol 101 (3) ◽  
pp. 627-652 ◽  
Author(s):  
K.A. Lawson ◽  
R.A. Pedersen
Keyword(s):  
Cell Fate ◽  
Doubling Time ◽  
Primitive Streak ◽  
Yolk Sac ◽  
Population Doubling ◽  
Population Doubling Time ◽  
Germ Layer ◽  
Posterior Half ◽  
Visceral Yolk Sac

The fate of the embryonic endoderm (generally called visceral embryonic endoderm) of prestreak and early primitive streak stages of the mouse embryo was studied in vitro by microinjecting horseradish peroxidase into single axial endoderm cells of 6.7-day-old embryos and tracing the labelled descendants either through gastrulation (1 day of culture) or to early somite stages (2 days of culture). Descendants of endoderm cells from the anterior half of the axis were found at the extreme cranial end of the embryo after 1 day and in the visceral yolk sac endoderm after 2 days, i.e. they were displaced anteriorly and anterolaterally. Descendants of cells originating over and near the anterior end of the early primitive streak, i.e. posterior to the distal tip of the egg cylinder, were found after 1 day over the entire embryonic axis and after 2 days in the embryonic endoderm at the anterior intestinal portal, in the foregut, along the trunk and postnodally, as well as anteriorly and posteriorly in the visceral yolk sac. Endoderm covering the posterior half of the early primitive streak contributed to postnodal endoderm after 1 day (at the late streak stage) and mainly to posterior visceral yolk sac endoderm after 2 days. Clonal descendants of axial endoderm were located after 2 days either over the embryo or in the yolk sac; the few exceptions spanned the caudal end of the embryo and the posterior yolk sac. The clonal analysis also showed that the endoderm layer along the posterior half of the axis of prestreak- and early-streak-stage embryos is heterogeneous in its germ layer fate. Whereas the germ layer location of descendants from anterior sites did not differ after 1 day from that expected from the initial controls (approx. 90% exclusively in endoderm), only 62% of the successfully injected posterior sites resulted in labelled cells exclusively in endoderm; the remainder contributed partially or entirely to ectoderm and mesoderm. This loss from the endoderm layer was compensated by posterior-derived cells that remained in endoderm having more surviving descendants (8.4 h population doubling time) than did anterior-derived cells (10.5 h population doubling time). There was no indication of cell death at the prestreak and early streak stages; at least 93% of the cells were proliferating and more than half of the total axial population were in, or had completed, a third cell cycle after 22 h culture.(ABSTRACT TRUNCATED AT 400 WORDS)

Neuroectodermal fate of epiblast cells in the distal region of the mouse egg cylinder: implication for body plan organization during early embryogenesis

Development ◽  
1995 ◽  
Vol 121 (1) ◽  
pp. 87-98 ◽  
Author(s):  
G.A. Quinlan ◽  
E.A. Williams ◽  
S.S. Tan ◽  
P.P. Tam
Keyword(s):  
Cell Fate ◽  
Neural Tube ◽  
Primitive Streak ◽  
Distal Region ◽  
Small Population ◽  
Surface Ectoderm ◽  
Minor Contribution ◽  
Stage Embryo ◽  
A Minor

The developmental fate of cells in the distal region (distal cap) of the epiblast was analysed by fate mapping studies. The displacement and differentiation of cells labelled in situ with carbocyanine dyes and lacZ-expressing cells grafted to the distal cap were studied over a 48-hour period of in vitro development. The distal cap epiblast differentiates predominantly into neurectodermal cells. Cells at the anterior site of the distal cap colonise the fore-, mid- and hindbrain and contribute to non-neural ectoderm cells of the amnion and craniofacial surface ectoderm. Those cells in the most distal region of the epiblast contribute to all three brain compartments as well as the spinal cord and the posterior neuropore. Cells at the posterior site of the distal cap are mainly localised to the caudal parts of the neural tube. A minor contribution to the embryonic (paraxial and lateral) and extraembryonic (allantoic and yolk sac) mesoderm is also found. Epiblast cells located outside the distal cap give rise to surface ectoderm and other non-ectodermal derivatives, with only a minor contribution to the neuroectoderm. Results of this study provide compelling evidence that the precursor population of the neural tube is contained in the distal cap epiblast of the early-primitive-streak-stage embryo. Furthermore, the regionalisation of cell fate within this small population suggest that a preliminary craniocaudal patterning may have occurred in the neural primordium before neurulation.

Early mouse endoderm is patterned by soluble factors from adjacent germ layers

Development ◽  
2000 ◽  
Vol 127 (8) ◽  
pp. 1563-1572 ◽  
Author(s):  
J.M. Wells ◽  
D.A. Melton
Keyword(s):  
Primitive Streak ◽  
In Vitro Assay ◽  
Specific Gene ◽  
Dependent Manner ◽  
Concentration Dependent Manner ◽  
Germ Layers ◽  
Vitro Assay ◽  
Organ Specific ◽  
Early Mouse

Endoderm that forms the respiratory and digestive tracts is a sheet of approximately 500–1000 cells around the distal cup of an E7.5 mouse embryo. Within 2 days, endoderm folds into a primitive gut tube from which numerous organs will bud. To characterize the signals involved in the developmental specification of this early endoderm, we have employed an in vitro assay using germ layer explants and show that adjacent germ layers provide soluble, temporally specific signals that induce organ-specific gene expression in endoderm. Furthermore, we show that FGF4 expressed in primitive streak-mesoderm can induce the differentiation of endoderm in a concentration-dependent manner. We conclude that the differentiation of gastrulation-stage endoderm is directed by adjacent mesoderm and ectoderm, one of the earliest reported patterning events in formation of the vertebrate gut tube.

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