scholarly journals The Activity of Pax3 and Zic1 Regulates Three Distinct Cell Fates at the Neural Plate Border

2007 ◽  
Vol 18 (6) ◽  
pp. 2192-2202 ◽  
Author(s):  
Chang-Soo Hong ◽  
Jean-Pierre Saint-Jeannet

In Xenopus, the neural plate border gives rise to at least three cell populations: the neural crest, the preplacodal ectoderm, and the hatching gland. To understand the molecular mechanisms that regulate the formation of these lineages, we have analyzed the role of two transcription factors, Pax3 and Zic1, which are among the earliest genes activated in response to neural plate border-inducing signals. At the end of gastrulation, Pax3 and Zic1 are coexpressed in the neural crest forming region. In addition, Pax3 is expressed in progenitors of the hatching gland, and Zic1 is detected in the preplacodal ectoderm. Using gain of function and knockdown approaches in whole embryos and animal explants, we demonstrate that Pax3 and Zic1 are necessary and sufficient to promote hatching gland and preplacodal fates, respectively, whereas their combined activity is essential to specify the neural crest. Moreover, we show that by manipulating the levels of Pax3 and Zic1 it is possible to shift fates among these cells. These findings provide novel information on the mechanisms regulating cell fate decisions at the neural plate border.

Development ◽  
2013 ◽  
Vol 140 (21) ◽  
pp. 4435-4444 ◽  
Author(s):  
S. Reichert ◽  
R. A. Randall ◽  
C. S. Hill

Development ◽  
1997 ◽  
Vol 124 (21) ◽  
pp. 4351-4359 ◽  
Author(s):  
P.D. Henion ◽  
J.A. Weston

The trunk neural crest of vertebrate embryos is a transient collection of precursor cells present along the dorsal aspect of the neural tube. These cells migrate on two distinct pathways and give rise to specific derivatives in precise embryonic locations. One group of crest cells migrates early on a ventral pathway and generates neurons and glial cells. A later-dispersing group migrates laterally and gives rise to melanocytes in the skin. These observations raise the possibility that the appearance of distinct derivatives in different embryonic locations is a consequence of lineage restrictions specified before or soon after the onset of neural crest cell migration. To test this notion, we have assessed when and in what order distinct cell fates are specified during neural crest development. We determined the proportions of different types of precursor cells in cultured neural crest populations immediately after emergence from the neural tube and at intervals as development proceeds. We found that the initial neural crest population was a heterogeneous mixture of precursors almost half of which generated single-phenotype clones. Distinct neurogenic and melanogenic sublineages were also present in the outgrowth population almost immediately, but melanogenic precursors dispersed from the neural tube only after many neurogenic precursors had already done so. A discrete fate-restricted neuronal precursor population was distinguished before entirely separate fate-restricted melanocyte and glial precursor populations were present, and well before initial neuronal differentiation. Taken together, our results demonstrate that lineage-restricted subpopulations constitute a major portion of the initial neural crest population and that neural crest diversification occurs well before overt differentiation by the asynchronous restriction of distinct cell fates. Thus, the different morphogenetic and differentiative behavior of neural crest subsets in vivo may result from earlier cell fate-specification events that generate developmentally distinct subpopulations that respond differentially to environmental cues.


2019 ◽  
Vol 102 (3) ◽  
pp. 598-606
Author(s):  
Shanshan Guo ◽  
Xiuhong Cui ◽  
Xiangxiang Jiang ◽  
Shuguang Duo ◽  
Shiwen Li ◽  
...  

Abstract The placenta, which originates from the trophectoderm (TE), is the first organ to form during mammalian embryogenesis. Recent studies based on bioinformatics analysis have revealed that heterogeneous gene expression initiates cell-fate decisions and directs two distinct cell fates by modulating the balance of pluripotency and differentiation as early as the four-cell stage. However, direct developmental evidence to support this is still lacking. To address at which stage the cell fate of the TE and inner cell mass (ICM) is determined, in this study, we administered a microinjection of Cre mRNA into a single blastomere of the mTmG mouse at different cleavage stages before implantation to examine the distributions of the descendants of the single-labeled cell in the mouse fetus and the placenta at E12.5. We found that the descendants of the labeled cells at the two-cell stage contributed to both the placenta and the fetus. Notably, the derivatives of the labeled cells at the four-cell stage fell into three categories: (1) distributed in both embryonic and extraembryonic lineages, (2) distributed only in mouse placental trophoblast layers, or (3) distributed only in the lineage derived from the ICM. In addition, these results fell in line with single-cell studies focusing on gene expression patterns that characterize particular lineages within the blastocyst. In conclusion, this study shows that the four-cell blastomeres differ in their individual developmental properties insofar as they contribute to either or both the ICM and trophoblast fate.


eLife ◽  
2017 ◽  
Vol 6 ◽  
Author(s):  
Daniela Roellig ◽  
Johanna Tan-Cabugao ◽  
Sevan Esaian ◽  
Marianne E Bronner

The ‘neural plate border’ of vertebrate embryos contains precursors of neural crest and placode cells, both defining vertebrate characteristics. How these lineages segregate from neural and epidermal fates has been a matter of debate. We address this by performing a fine-scale quantitative temporal analysis of transcription factor expression in the neural plate border of chick embryos. The results reveal significant overlap of transcription factors characteristic of multiple lineages in individual border cells from gastrula through neurula stages. Cell fate analysis using a Sox2 (neural) enhancer reveals that cells that are initially Sox2+ cells can contribute not only to neural tube but also to neural crest and epidermis. Moreover, modulating levels of Sox2 or Pax7 alters the apportionment of neural tube versus neural crest fates. Our results resolve a long-standing question and suggest that many individual border cells maintain ability to contribute to multiple ectodermal lineages until or beyond neural tube closure.


Genetics ◽  
1995 ◽  
Vol 141 (4) ◽  
pp. 1491-1505
Author(s):  
D F Lyman ◽  
B Yedvobnick

Abstract The neurogenic Notch locus of Drosophila encodes a receptor necessary for cell fate decisions within equivalence groups, such as proneural clusters. Specification of alternate fates within clusters results from inhibitory communication among cells having comparable neural fate potential. Genetically, Hairless (H) acts as an antagonist of most neurogenic genes and may insulate neural precursor cells from inhibition. H function is required for commitment to the bristle sensory organ precursor (SOP) cell fate and for daughter cell fates. Using Notch gain-of-function alleles and conditional expression of an activated Notch transgene, we show that enhanced signaling produces H-like loss-of-function phenotypes by suppressing bristle SOP cell specification or by causing an H-like transformation of sensillum daughter cell fates. Furthermore, adults carrying Notch gain of function and H alleles exhibit synergistic enhancement of mutant phenotypes. Over-expression of an H+ transgene product suppressed virtually all phenotypes generated by Notch gain-of-function genotypes. Phenotypes resulting from over-expression of the H+ transgene were blocked by the Notch gain-of-function products, indicating a balance between Notch and H activity. The results suggest that H insulates SOP cells from inhibition and indicate that H activity is suppressed by Notch signaling.


Author(s):  
Lucy LeBlanc ◽  
Nereida Ramirez ◽  
Jonghwan Kim

AbstractHippo effectors YAP and TAZ control cell fate and survival through various mechanisms, including transcriptional regulation of key genes. However, much of this research has been marked by conflicting results, as well as controversy over whether YAP and TAZ are redundant. A substantial portion of the discordance stems from their contradictory roles in stem cell self-renewal vs. differentiation and cancer cell survival vs. apoptosis. In this review, we present an overview of the multiple context-dependent functions of YAP and TAZ in regulating cell fate decisions in stem cells and organoids, as well as their mechanisms of controlling programmed cell death pathways in cancer.


Circulation ◽  
2008 ◽  
Vol 118 (suppl_18) ◽  
Author(s):  
Virginia Guarani ◽  
Franck Dequiedt ◽  
Andreas M Zeiher ◽  
Stefanie Dimmeler ◽  
Michael Potente

The Notch signaling pathway is a versatile regulator of cell fate decisions and plays an essential role for embryonic and postnatal vascular development. As only modest differences in Notch pathway activity suffice to determine dramatic differences in blood vessel development, this pathway is tightly regulated by a variety of molecular mechanisms. Reversible acetylation has emerged as an important post-translational modification of several non-histone proteins, which are targeted by histone deacetylases (HDACs). Here, we report that specifically the Notch1 intracellular domain (NICD) is itself an acetylated protein and that its acetylation level is tightly regulated by the SIRT1 deacetylase, which we have previously identified as a key regulator of endothelial angiogenic functions during vascular growth. Coexpression of NICD with histone acetyltransferases such as p300 or PCAF induced a dose- and time-dependent acetylation of NICD. Blocking HDAC activity using the class III HDAC inhibitor nicotinamid (NAM), but not the class I/II HDAC inhibior trichostatin A, resulted in a significant increase of NICD acetylation suggesting that NICD is targetd by class III HDACs for deacetylation. Among the class III HDACs with deacetylase activity (SIRT1, 2, 3, 5), knock down of specifically SIRT1 resulted in enhanced acetylation of NICD. Moreover, wild type SIRT1, but not a catalytically inactive mutant catalyzed the deacetylation of NICD in a nicotinamid-dependent manner. SIRT1, but SIRT2, SIRT3 or SIRT5, associated with NICD through its catalytic domain demonstrating that SIRT1 is a direct NICD deacetylase. Enhancing NICD acetylation by either overexpression of p300 or inhibition of SIRT1 activity using NAM or RNAi-mediated knock down resulted in enhanced NICD protein stability by blocking its ubiquitin-mediated degradation. Consistent with these results, loss of SIRT1 amplified Notch target gene expression in endothelial cells in response to NICD overexpression or treatment with the Notch ligand Dll4. In summary, our results identify reversible acetylation of NICD as a novel molecular mechanism to control Notch signaling and suggest that deacetylation of NICD by SIRT1 plays a key role in the dynamic regulation of Notch signaling in endothelial cells.


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