scholarly journals A dual function of FGF signaling in Xenopus left-right axis formation

2018 ◽  
Author(s):  
Isabelle Schneider ◽  
Jennifer Kreis ◽  
Axel Schweickert ◽  
Martin Blum ◽  
Philipp Vick
Keyword(s):  
Model Organisms ◽  
Dual Function ◽  
Axis Formation ◽  
Mesoderm Induction ◽  
Nodal Signaling ◽  
Fgf Signaling ◽  
Mesoderm Development ◽  
Flow Sensing ◽  
Early Gastrula

AbstractOrgan left-right (LR) asymmetry is a conserved vertebrate feature, which is regulated by left-sided activation of Nodal signaling. Nodal asymmetry is established by a leftward fluid-flow generated at the ciliated LR organizer (LRO). While the role of fibroblast growth factor (FGF) signaling pathways during mesoderm development are conserved, diverging results from different model organisms suggested a non-conserved function in LR asymmetry. Here, we demonstrate that FGF is required during gastrulation in a dual function at consecutive stages of Xenopus embryonic development. In the early gastrula, FGF is necessary for LRO precursor induction, acting in parallel to FGF-mediated mesoderm induction. During late gastrulation, the FGF/Ca2+-branch is required for specification of the flow sensing lateral LRO cells, a function related to FGF-mediated mesoderm morphogenesis. This second function in addition requires input from the calcium channel Polycystin-2. Thus, analogous to mesoderm development, FGF activity is required in a dual role for laterality specification, namely for generating and sensing of leftward flow. Moreover, our data show that FGF functions in LR asymmetric development are conserved across vertebrate species, from fish to mammals.

scholarly journals FGF signaling induces mesoderm in members of Spiralia

2020 ◽  
Author(s):  
Carmen Andrikou ◽  
Andreas Hejnol
Keyword(s):  
Gene Expression ◽  
Mesoderm Induction ◽  
Fgf Signaling ◽  
Mesoderm Development ◽  
Molecular Patterning ◽  
Gene Expression Analyses ◽  
Mesoderm Formation ◽  
And Migration ◽  
Mesoderm Patterning

AbstractFGF signaling is involved in mesoderm induction in deuterostomes, but not in flies and nematodes, where it has a role in mesoderm patterning and migration. However, comparable studies in other protostomic taxa are missing in order to decipher whether this mesoderm-inducing function of FGF extends beyond the lineage of deuterostomes. Here, we investigated the role of FGF signaling during mesoderm development in three species of lophophorates, a clade within the protostome group Spiralia. Our gene expression analyses show that the molecular patterning of mesoderm development is overall conserved between brachiopods and phoronids, but the spatial and temporal recruitment of transcription factors differs significantly. Moreover, inhibitor experiments demonstrate that FGF signaling is involved in mesoderm formation, morphogenetic movements of gastrulation and posterior axial elongation. Our findings suggest that the inductive role of FGF in mesoderm possibly predates the origin of deuterostomes.

scholarly journals FGF signaling acts on different levels of mesoderm development within Spiralia

Development ◽  
2021 ◽  
Author(s):  
Carmen Andrikou ◽  
Andreas Hejnol
Keyword(s):  
Gene Expression ◽  
Mesoderm Induction ◽  
Fgf Signaling ◽  
Mesoderm Development ◽  
Molecular Patterning ◽  
Gene Expression Analyses ◽  
And Migration ◽  
Mesoderm Patterning ◽  
Different Levels

FGF signaling is involved in mesoderm induction in members of deuterostomes (e.g. tunicates, hemichordates), but not in flies and nematodes, where it has a role in mesoderm patterning and migration. However, comparable studies in other protostome taxa are missing in order to decipher whether this mesoderm-inducing function of FGF extends beyond the lineage of deuterostomes. Here, we investigated the role of FGF signaling in mesoderm development in three species of lophophorates, a clade within the protostome group Spiralia. Our gene expression analyses show that the mesodermal molecular patterning is overall conserved between brachiopods and phoronids, but the spatial and temporal recruitment of transcription factors differs significantly. Moreover, the use of the inhibitor SU5402 demonstrates that FGF signaling is involved in different steps of mesoderm development, as well as in morphogenetic movements of gastrulation and axial elongation. Our findings suggest that the mesoderm-inducing role of FGF extends beyond the group of deuterostomes.

scholarly journals Mesoderm induction by activin requires FGF-mediated intracellular signals

Development ◽  
1994 ◽  
Vol 120 (2) ◽  
pp. 463-472 ◽  
Author(s):  
C. LaBonne ◽  
M. Whitman
Keyword(s):  
Plasma Membrane ◽  
Molecular Markers ◽  
Signaling Pathway ◽  
Mesoderm Induction ◽  
Fgf Signaling ◽  
Transcriptional Responses ◽  
Fgf Receptor ◽  
Signal Transducers ◽  
Intracellular Signals

We have examined the role of FGF signaling during activin-mediated mesoderm induction in Xenopus. Using dominant inhibitory mutants of FGF signal transducers to disrupt the FGF-signaling pathway at the plasma membrane or in the cytosol prevents animal cap blastomeres from expressing several mesodermal markers in response to exogenous activin. Dominant inhibitory mutants of the FGF receptor, c-ras or c-raf inhibit the ability of activin to induce molecular markers of both dorsal and ventral mesoderm including Xbra, Mix1 and Xnot. Some transcriptional responses to activin such as goosecoid and Xwnt8 are inhibited less effectively than others, however, suggesting that there may differing requirements for an FGF signal in the responses of mesoderm-specific genes to activin induction. Despite the requirement for this signaling pathway during activin induction, downstream components of this pathway are not activated in response to activin, suggesting that activin does not signal directly through this pathway.

The cleavage stage origin of Spemann's Organizer: analysis of the movements of blastomere clones before and during gastrulation in Xenopus

Development ◽  
1994 ◽  
Vol 120 (5) ◽  
pp. 1179-1189 ◽  
Author(s):  
D.V. Bauer ◽  
S. Huang ◽  
S.A. Moody
Keyword(s):  
Neural Induction ◽  
Axis Formation ◽  
Mesoderm Induction ◽  
Animal Pole ◽  
Genetic Manipulations ◽  
Spemann's Organizer ◽  
History Of ◽  
Clonal Origin ◽  
The Relationship ◽  
Early Gastrula

Recent investigations into the roles of early regulatory genes, especially those resulting from mesoderm induction or first expressed in the gastrula, reveal a need to elucidate the developmental history of the cells in which their transcripts are expressed. Although fates both of the early blastomeres and of regions of the gastrula have been mapped, the relationship between the two sets of fate maps is not clear and the clonal origin of the regions of the stage 10 embryo are not known. We mapped the positions of each blastomere clone during several late blastula and early gastrula stages to show where and when these clones move. We found that the dorsal animal clone (A1) begins to move away from the animal pole at stage 8, and the dorsal animal marginal clone (B1) leaves the animal cap by stage 9. The ventral animal clones (A4 and B4) spread into the dorsal animal cap region as the dorsal clones recede. At stage 10, the ventral animal clones extend across the entire dorsal animal cap. These changes in the blastomere constituents of the animal cap during epiboly may contribute to the changing capacity of the cap to respond to inductive growth factors. Pregastrulation movements of clones also result in the B1 clone occupying the vegetal marginal zone to become the primary progenitor of the dorsal lip of the blastopore (Spemann's Organizer). This report provides the fundamental descriptions of clone locations during the important periods of axis formation, mesoderm induction and neural induction. These will be useful for the correct targeting of genetic manipulations of early regulatory events.

FAST-1 is a key maternal effector of mesoderm inducers in the early Xenopus embryo

Development ◽  
1999 ◽  
Vol 126 (24) ◽  
pp. 5621-5634 ◽  
Author(s):  
M. Watanabe ◽  
M. Whitman
Keyword(s):  
Gene Expression ◽  
Transcription Factor ◽  
Ectopic Expression ◽  
Axis Formation ◽  
Mesoderm Induction ◽  
Transcriptional Program ◽  
Blocking Antibody ◽  
Responsive Element ◽  
Axial Development

We have examined the role of the maternally encoded transcription factor FAST-1 in the establishment of the mesodermal transcriptional program in Xenopus embryos. FAST-1 has been shown to associate with Smad2 and Smad4, transducers of TGFbeta superfamily signals, in response to stimulation by several TGFbeta superfamily ligands. The FAST-1/Smad2/Smad4 complex binds and activates a 50 bp activin responsive element identified in the promoter of the meso-endodermal marker Mix.2. We have now used three complementary approaches to demonstrate that FAST-1 is a central regulator of mesoderm induction by ectopic TGFbeta superfamily ligands and during endogenous patterning: ectopic expression of mutationally activated FAST-1, ectopic expression of dominant inhibitory FAST-1, and injection of a blocking antibody specific for FAST-1. Expression of constitutively transcriptionally active FAST-1 fusion protein (FAST-VP16(A)) in prospective ectoderm can directly induce the same set of general and dorsal mesodermal genes, as well as some endodermal genes, as are induced by activin or Vg1. In intact embryos, this construct can induce secondary axes similar to those induced by activin or Vg1. Conversely, expression of a FAST-1-repressor fusion (FAST-En(R)) in prospective ectoderm blocks induction of mesodermal genes by activin, while expression of FAST-En(R) in intact embryos prevents general/dorsal mesodermal gene expression and axial development. Injection of a blocking antibody specific for FAST-1 prevents induction of mesodermal response genes by activin or Vg1, but not by FGF. In intact embryos, this antibody can prevent the expression of early mesodermal markers and inhibit axis formation, demonstrating that FAST-1 is a necessary component of the first steps in the specification of mesoderm.

scholarly journals A dual function of FGF signaling in Xenopus left-right axis formation

Development ◽  
2019 ◽  
Vol 146 (9) ◽  
pp. dev173575 ◽  
Author(s):  
Isabelle Schneider ◽  
Jennifer Kreis ◽  
Axel Schweickert ◽  
Martin Blum ◽  
Philipp Vick
Keyword(s):  
Dual Function ◽  
Axis Formation ◽  
Fgf Signaling

Centrosome Aurora A gradient ensures single polarity axis in C. elegans embryos

2020 ◽  
Vol 48 (3) ◽  
pp. 1243-1253 ◽  
Author(s):  
Sukriti Kapoor ◽  
Sachin Kotak
Keyword(s):  
Symmetry Breaking ◽  
Cell Fate ◽  
Cell Cortex ◽  
Axis Formation ◽  
Aurora A Kinase ◽  
Aurora A ◽  
C Elegans ◽  
Cell Embryo ◽  
Polarity Establishment

Cellular asymmetries are vital for generating cell fate diversity during development and in stem cells. In the newly fertilized Caenorhabditis elegans embryo, centrosomes are responsible for polarity establishment, i.e. anterior–posterior body axis formation. The signal for polarity originates from the centrosomes and is transmitted to the cell cortex, where it disassembles the actomyosin network. This event leads to symmetry breaking and the establishment of distinct domains of evolutionarily conserved PAR proteins. However, the identity of an essential component that localizes to the centrosomes and promotes symmetry breaking was unknown. Recent work has uncovered that the loss of Aurora A kinase (AIR-1 in C. elegans and hereafter referred to as Aurora A) in the one-cell embryo disrupts stereotypical actomyosin-based cortical flows that occur at the time of polarity establishment. This misregulation of actomyosin flow dynamics results in the occurrence of two polarity axes. Notably, the role of Aurora A in ensuring a single polarity axis is independent of its well-established function in centrosome maturation. The mechanism by which Aurora A directs symmetry breaking is likely through direct regulation of Rho-dependent contractility. In this mini-review, we will discuss the unconventional role of Aurora A kinase in polarity establishment in C. elegans embryos and propose a refined model of centrosome-dependent symmetry breaking.

scholarly journals Moonlighting in Bacillus subtilis: The Small Proteins SR1P and SR7P Regulate the Moonlighting Activity of Glyceraldehyde 3-Phosphate Dehydrogenase A (GapA) and Enolase in RNA Degradation

2021 ◽  
Vol 9 (5) ◽  
pp. 1046
Author(s):  
Inam Ul Haq ◽  
Sabine Brantl
Keyword(s):  
Bacillus Subtilis ◽  
Antisense Rna ◽  
Rna Binding ◽  
Rna Degradation ◽  
Metabolic Enzyme ◽  
Dual Function ◽  
Small Proteins ◽  
Moonlighting Proteins ◽  
Rnase Y

Moonlighting proteins are proteins with more than one function. During the past 25 years, they have been found to be rather widespread in bacteria. In Bacillus subtilis, moonlighting has been disclosed to occur via DNA, protein or RNA binding or protein phosphorylation. In addition, two metabolic enzymes, enolase and phosphofructokinase, were localized in the degradosome-like network (DLN) where they were thought to be scaffolding components. The DLN comprises the major endoribonuclease RNase Y, 3′-5′ exoribonuclease PnpA, endo/5′-3′ exoribonucleases J1/J2 and helicase CshA. We have ascertained that the metabolic enzyme GapA is an additional component of the DLN. In addition, we identified two small proteins that bind scaffolding components of the degradosome: SR1P encoded by the dual-function sRNA SR1 binds GapA, promotes the GapA-RNase J1 interaction and increases the RNase J1 activity. SR7P encoded by the dual-function antisense RNA SR7 binds to enolase thereby enhancing the enzymatic activity of enolase bound RNase Y. We discuss the role of small proteins in modulating the activity of two moonlighting proteins.

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