FGF3 and FGF8 mediate a rhombomere 4 signaling activity in the zebrafish hindbrain

Development ◽  
2002 ◽  
Vol 129 (16) ◽  
pp. 3825-3837 ◽  
Author(s):  
Lisa Maves ◽  
William Jackman ◽  
Charles B. Kimmel

The segmentation of the vertebrate hindbrain into rhombomeres is highly conserved, but how early hindbrain patterning is established is not well understood. We show that rhombomere 4 (r4) functions as an early-differentiating signaling center in the zebrafish hindbrain. Time-lapse analyses of zebrafish hindbrain development show that r4 forms first and hindbrain neuronal differentiation occurs first in r4. Two signaling molecules, FGF3 and FGF8, which are both expressed early in r4, are together required for the development of rhombomeres adjacent to r4, particularly r5 and r6. Transplantation of r4 cells can induce expression of r5/r6 markers, as can misexpression of either FGF3 or FGF8. Genetic mosaic analyses also support a role for FGF signaling acting from r4. Taken together, our findings demonstrate a crucial role for FGF-mediated inter-rhombomere signaling in promoting early hindbrain patterning and underscore the significance of organizing centers in patterning the vertebrate neural plate.

2011 ◽  
Vol 358 (2) ◽  
pp. 356-367 ◽  
Author(s):  
Seong-Kyu Choe ◽  
Xiaolan Zhang ◽  
Nicolas Hirsch ◽  
Juerg Straubhaar ◽  
Charles G. Sagerström

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Jonathan M. Werner ◽  
Maraki Y. Negesse ◽  
Dominique L. Brooks ◽  
Allyson R. Caldwell ◽  
Jafira M. Johnson ◽  
...  

AbstractPrimary neurulation is the process by which the neural tube, the central nervous system precursor, is formed from the neural plate. Incomplete neural tube closure occurs frequently, yet underlying causes remain poorly understood. Developmental studies in amniotes and amphibians have identified hingepoint and neural fold formation as key morphogenetic events and hallmarks of primary neurulation, the disruption of which causes neural tube defects. In contrast, the mode of neurulation in teleosts has remained highly debated. Teleosts are thought to have evolved a unique mode of neurulation, whereby the neural plate infolds in absence of hingepoints and neural folds, at least in the hindbrain/trunk where it has been studied. Using high-resolution imaging and time-lapse microscopy, we show here the presence of these morphological landmarks in the zebrafish anterior neural plate. These results reveal similarities between neurulation in teleosts and other vertebrates and hence the suitability of zebrafish to understand human neurulation.


Development ◽  
1997 ◽  
Vol 124 (15) ◽  
pp. 2923-2934 ◽  
Author(s):  
K.M. Wassarman ◽  
M. Lewandoski ◽  
K. Campbell ◽  
A.L. Joyner ◽  
J.L. Rubenstein ◽  
...  

Analysis of mouse embryos homozygous for a loss-of-function allele of Gbx2 demonstrates that this homeobox gene is required for normal development of the mid/hindbrain region. Gbx2 function appears to be necessary at the neural plate stage for the correct specification and normal proliferation or survival of anterior hindbrain precursors. It is also required to maintain normal patterns of expression at the mid/hindbrain boundary of Fgf8 and Wnt1, genes that encode signaling molecules thought to be key components of the mid/hindbrain (isthmic) organizer. In the absence of Gbx2 function, isthmic nuclei, the cerebellum, motor nerve V, and other derivatives of rhombomeres 1–3 fail to form. Additionally, the posterior midbrain in the mutant embryos appears to be extended caudally and displays abnormalities in anterior/posterior patterning. The failure of anterior hindbrain development is presumably due to the loss of Gbx2 function in the precursors of the anterior hindbrain. However, since Gbx2 expression is not detected in the midbrain it seems likely that the defects in midbrain anterior/posterior patterning result from an abnormal isthmic signaling center. These data provide genetic evidence for a link between patterning of the anterior hindbrain and the establishment of the mid/hindbrain organizer, and identify Gbx2 as a gene required for these processes to occur normally.


Development ◽  
2000 ◽  
Vol 127 (13) ◽  
pp. 2945-2954 ◽  
Author(s):  
A.A. Gershon ◽  
J. Rudnick ◽  
L. Kalam ◽  
K. Zimmerman

The development of the vertebrate nervous system depends upon striking a balance between differentiating neurons and neural progenitors in the early embryo. Our findings suggest that the homeodomain-containing gene Xdbx regulates this balance by maintaining neural progenitor populations within specific regions of the neuroectoderm. In posterior regions of the Xenopus embryo, Xdbx is expressed in a bilaterally symmetric stripe that lies at the middle of the mediolateral axis of the neural plate. This stripe of Xdbx expression overlaps the expression domain of the proneural basic/helix-loop-helix-containing gene, Xash3, and is juxtaposed to the expression domains of Xenopus Neurogenin related 1 and N-tubulin, markers of early neurogenesis in the embryo. Xdbx overexpression inhibits neuronal differentiation in the embryo and when co-injected with Xash3, Xdbx inhibits the ability of Xash3 to induce ectopic neurogenesis. One role of Xdbx during normal development may therefore be to restrict spatially neuronal differentiation within the neural plate, possibly by altering the neuronal differentiation function of Xash3.


Development ◽  
1998 ◽  
Vol 125 (6) ◽  
pp. 983-994 ◽  
Author(s):  
M.L. Concha ◽  
R.J. Adams

We have taken advantage of the optical transparency of zebrafish embryos to investigate the patterns of cell division, movement and shape during early stages of development of the central nervous system. The surface-most epiblast cells of gastrula and neurula stage embryos were imaged and analysed using a computer-based, time-lapse acquisition system attached to a differential interference contrast (DIC) microscope. We find that the onset of gastrulation is accompanied by major changes in cell behaviour. Cells collect into a cohesive sheet, apparently losing independent motility and integrating their behaviour to move coherently over the yolk in a direction that is the result of two influences: towards the vegetal pole in the movements of epiboly and towards the dorsal midline in convergent movements that strengthen throughout gastrulation. Coincidentally, the plane of cell division becomes aligned to the surface plane of the embryo and oriented in the anterior-posterior (AP) direction. These behaviours begin at the blastoderm margin and propagate in a gradient towards the animal pole. Later in gastrulation, cells undergo increasingly mediolateral-directed elongation and autonomous convergence movements towards the dorsal midline leading to an enormous extension of the neural axis. Around the equator and along the dorsal midline of the gastrula, persistent AP orientation of divisions suggests that a common mechanism may be involved but that neither oriented cell movements nor shape can account for this alignment. When the neural plate begins to differentiate, there is a gradual transition in the direction of cell division from AP to the mediolateral circumference (ML). ML divisions occur in both the ventral epidermis and dorsal neural plate. In the neural plate, ML becomes the predominant orientation of division during neural keel and nerve rod stages and, from late neural keel stage, divisions are concentrated at the dorsal midline and generate bilateral progeny (C. Papan and J. A. Campos-Ortega (1994) Roux's Arch. Dev. Biol. 203, 178–186). Coincidentally, cells on the ventral surface also orient their divisions in the ML direction, cleaving perpendicular to the direction in which they are elongated. The ML alignment of epidermal divisions is well correlated with cell shape but ML divisions within the neuroepithelium appear to be better correlated with changes in tissue morphology associated with neurulation.


2020 ◽  
Author(s):  
Jakub Sumbal ◽  
Tereza Vranova ◽  
Zuzana Koledova

SummarySingle cell assays revealed that growth factor signaling dynamics is actively sensed by a cell and ultimately controls cell fate. However, the effects of growth factor signaling dynamics at the tissue level have been unknown. We used mammary epithelial organoids, time-lapse imaging, fibroblast growth factor 2 (FGF2) variants of different stabilities, mathematical modeling, and perturbation analysis to study the role of FGF2 signaling dynamics in epithelial morphogenesis. We found that fluctuant and sustained FGF signaling dynamics induced distinct morphological and functional states of mammary epithelium through differential employment of intracellular effectors ERK and AKT. ERK activity domains determined epithelial branch size, while AKT activity drove epithelial stratification. Furthermore, FGF signaling dynamics affected epithelial tissue mechanoresponsiveness to extracellular matrix, thereby impinging upon branch elongation. Our study provides new insights into regulation of epithelial patterning and branching morphogenesis by FGF signaling dynamics and into downstream signaling effectors that regulate cellular outcomes.


2021 ◽  
Author(s):  
Jian Ma ◽  
Xiaoyun Fang ◽  
Min Chen ◽  
Yao Wang ◽  
Li Zhang

Abstract Background: Therapeutic applications of retinal progenitor cells (RPCs) are hindered by their limited proliferation and differentiation capacity and poor ability to migrate into damaged retinal tissue. Our study aimed to explore the effects of HA-CD44 interactions on the regulation of RPCs migration, proliferation and differentiation, and to investigate the underlying regulation mechanisms.Methods: Mouse RPCs were isolated and amplified. Western blot and flow cytometry analyses were used to investigate the expression of CD44 in RPCs. The effects of HA-CD44 interactions on the RPCs behaviors, including migration, proliferation and differentiation, were investigated by MTT assay, CCK8 assay, vertical collagen gel invasion assay, time-lapse imaging, immunocytochemistry, RT-PCR and western blot assay. Furthermore, the downstream signals of HA-CD44 interactions were investigated.Results: CD44 was expressed in RPCs, and HA-CD44 interaction markedly improved RPCs adhesion and migration. The stimulation of miR-21 expression by HA-CD44 interaction was PKC/Nanog-dependent in RPCs. Treatment of RPCs with PKC- or Nanog-specific ASODN or miR-21 antagomir effectively blocked HA-mediated RPCs adhesion and migration. Moreover, ROK/Gab-1 associated PI3K/AKT signaling activation was required in the HA-CD44 interaction mediated RPCs proliferation and neuronal differentiation.Conclusions: Our findings demonstrated new roles for HA-CD44 interaction in regulating both migration, proliferation and neuronal differentiation of RPCs. HA-CD44 signaling could comprise a novel approach to control RPC fates, which may be instructive for the application of RPCs for future therapeutic application.


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