Development of branchiomotor neurons in zebrafish

Development ◽  
1997 ◽  
Vol 124 (13) ◽  
pp. 2633-2644 ◽  
Author(s):  
A. Chandrasekhar ◽  
C.B. Moens ◽  
J.T. Warren ◽  
C.B. Kimmel ◽  
J.Y. Kuwada
Keyword(s):  
Cell Migration ◽  
Neural Tube ◽  
Zebrafish Embryo ◽  
Mutational Analysis ◽  
Ventral Midline ◽  
Neuronal Specification ◽  
Motor Nuclei ◽  
Midline Cells ◽  
Insight Into

The mechanisms underlying neuronal specification and axonogenesis in the vertebrate hindbrain are poorly understood. To address these questions, we have employed anatomical methods and mutational analysis to characterize the branchiomotor neurons in the zebrafish embryo. The zebrafish branchiomotor system is similar to those in the chick and mouse, except for the location of the nVII and nIX branchiomotor neurons. Developmental analyses of genes expressed by branchiomotor neurons suggest that the different location of the nVII neurons in the zebrafish may result from cell migration. To gain insight into the mechanisms underlying the organization and axonogenesis of these neurons, we examined the development of the branchiomotor pathways in neuronal mutants. The valentino b337 mutation blocks the formation of rhombomeres 5 and 6, and severely affects the development of the nVII and nIX motor nuclei. The cyclops b16 mutation deletes ventral midline cells in the neural tube, and leads to a severe disruption of most branchiomotor nuclei and axon pathways. These results demonstrate that rhombomere-specific cues and ventral midline cells play important roles in the development of the branchiomotor pathways.

Mutational Analysis Provides Molecular Insight into the Carbohydrate-Binding Region of Calreticulin:  Pivotal Roles of Tyrosine-109 and Aspartate-135 in Carbohydrate Recognition†

Biochemistry ◽  
2004 ◽  
Vol 43 (1) ◽  
pp. 97-106 ◽  
Author(s):  
Mili Kapoor ◽  
Lars Ellgaard ◽  
Jayashree Gopalakrishnapai ◽  
Christiane Schirra ◽  
Emiliano Gemma ◽  
...  
Keyword(s):  
Mutational Analysis ◽  
Carbohydrate Binding ◽  
Binding Region ◽  
Carbohydrate Recognition ◽  
Insight Into

Expression of a lacZ transgene reveals floor plate cell morphology and macromolecular transfer to commissural axons

Development ◽  
1993 ◽  
Vol 119 (4) ◽  
pp. 1217-1228 ◽  
Author(s):  
R.M. Campbell ◽  
A.C. Peterson
Keyword(s):  
Neural Tube ◽  
Neuronal Cell ◽  
Floor Plate ◽  
Ventral Midline ◽  
Ample Evidence ◽  
Commissural Axons ◽  
Neuronal Cell Bodies ◽  
Lateral Branches ◽  
And Function ◽  
Beta Galactosidase

The floor plate is situated at the ventral midline of the neural tube and is an important intermediate target for commissural axons. During elongation, these axons converge bilaterally on the ventral midline neural tube and after crossing the floor plate make an abrupt rostral turn. Ample evidence indicates that the initial projection of commissural axons to the floor plate is guided by a chemotropic factor secreted by floor plate cells. However, the way in which the subsequent interaction of these axons with the floor plate leads them to make further trajectory changes remains undefined. In an effort to gain further understanding of the structure and function of floor plate cells, we have taken advantage of a line of transgenic mice in which these cells express beta-galactosidase and thus can be stained by histochemical means. In this line, a genomic imprinting mechanism restricts the expression of the lacZ transgene to only a proportion of the floor plate cells, allowing their morphology to be appreciated with particular clarity. Our analysis revealed that the basal processes of floor plate cells are flattened in their rostrocaudal dimension and possess fine lateral branches which are aligned with commissural axons. Unexpectedly, beta-galactosidase activity was also detected within longer transverse linear profiles traversing the floor plate whose ultrastructural appearance was not that of floor plate cells but instead corresponded to that of commissural axons. Enzyme activity was not detected in more proximal axonal segments or in the neuronal cell bodies from which these axons originated. Therefore, we propose that the transgene product, and potentially other proteins synthesized by floor plate cells, can be transferred to decussating axons.

Direct action of the nodal-related signal cyclops in induction of sonic hedgehog in the ventral midline of the CNS

Development ◽  
2000 ◽  
Vol 127 (18) ◽  
pp. 3889-3897 ◽  
Author(s):  
F. Muller ◽  
S. Albert ◽  
P. Blader ◽  
N. Fischer ◽  
M. Hallonet ◽  
...  
Keyword(s):  
Sonic Hedgehog ◽  
Neural Tube ◽  
Direct Action ◽  
Brain Regions ◽  
Floor Plate ◽  
Ventral Midline ◽  
Signal Transducers ◽  
Step Model ◽  
Ventral Neural Tube ◽  
Differential Responsiveness

The secreted molecule Sonic hedgehog (Shh) is crucial for floor plate and ventral brain development in amniote embryos. In zebrafish, mutations in cyclops (cyc), a gene that encodes a distinct signal related to the TGF(beta) family member Nodal, result in neural tube defects similar to those of shh null mice. cyc mutant embryos display cyclopia and lack floor plate and ventral brain regions, suggesting a role for Cyc in specification of these structures. cyc mutants express shh in the notochord but lack expression of shh in the ventral brain. Here we show that Cyc signalling can act directly on shh expression in neural tissue. Modulation of the Cyc signalling pathway by constitutive activation or inhibition of Smad2 leads to altered shh expression in zebrafish embryos. Ectopic activation of the shh promoter occurs in response to expression of Cyc signal transducers in the chick neural tube. Furthermore an enhancer of the shh gene, which controls ventral neural tube expression, is responsive to Cyc signal transducers. Our data imply that the Nodal related signal Cyc induces shh expression in the ventral neural tube. Based on the differential responsiveness of shh and other neural tube specific genes to Hedgehog and Cyc signalling, a two-step model for the establishment of the ventral midline of the CNS is proposed.

The distribution of fibronectin and tenascin along migratory pathways of the neural crest in the trunk of amphibian embryos

Development ◽  
1988 ◽  
Vol 103 (4) ◽  
pp. 743-756 ◽  
Author(s):  
H.H. Epperlein ◽  
W. Halfter ◽  
R.P. Tucker
Keyword(s):  
Cell Migration ◽  
Neural Crest ◽  
Neural Tube ◽  
Neural Crest Cell ◽  
Neural Crest Cells ◽  
Pigment Cells ◽  
Dorsal Fin ◽  
Amphibian Embryos ◽  
Neural Crest Cell Migration ◽  
Crest Cell

It is generally assumed that in amphibian embryos neural crest cells migrate dorsally, where they form the mesenchyme of the dorsal fin, laterally (between somites and epidermis), where they give rise to pigment cells, and ventromedially (between somites and neural tube), where they form the elements of the peripheral nervous system. While there is agreement about the crest migratory routes in the axolotl (Ambystoma mexicanum), different opinions exist about the lateral pathway in Xenopus. We investigated neural crest cell migration in Xenopus (stages 23, 32, 35/36 and 41) using the X. laevis-X. borealis nuclear marker system and could not find evidence for cells migrating laterally. We have also used immunohistochemistry to study the distribution of the extracellular matrix (ECM) glycoproteins fibronectin (FN) and tenascin (TN), which have been implicated in directing neural crest cells during their migrations in avian and mammalian embryos, in the neural crest migratory pathways of Xenopus and the axolotl. In premigratory stages of the crest, both in Xenopus (stage 22) and the axolotl (stage 25), FN was found subepidermally and in extracellular spaces around the neural tube, notochord and somites. The staining was particularly intense in the dorsal part of the embryo, but it was also present along the visceral and parietal layers of the lateral plate mesoderm. TN, in contrast, was found only in the anterior trunk mesoderm in Xenopus; in the axolotl, it was absent. During neural crest cell migration in Xenopus (stages 25–33) and the axolotl (stages 28–35), anti-FN stained the ECM throughout the embryo, whereas anti-TN staining was limited to dorsal regions. There it was particularly intense medially, i.e. in the dorsal fin, around the neural tube, notochord, dorsal aorta and at the medial surface of the somites (stage 35 in both species). During postmigratory stages in Xenopus (stage 40), anti-FN staining was less intense than anti-TN staining. In culture, axolotl neural crest cells spread differently on FN- and TN-coated substrata. On TN, the onset of cellular outgrowth was delayed for about 1 day, but after 3 days the extent of outgrowth was indistinguishable from cultures grown on FN. However, neural crest cells in 3-day-old cultures were much more flattened on FN than on TN. We conclude that both FN and TN are present in the ECM that lines the neural crest migratory pathways of amphibian embryos at the time when the neural crest cells are actively migrating. FN is present in the embryonic ECM before the onset of neural crest migration.(ABSTRACT TRUNCATED AT 400 WORDS)

scholarly journals Paracrine Pax6 activity regulates oligodendrocyte precursor cell migration in the chick embryonic neural tube

Development ◽  
2011 ◽  
Vol 138 (22) ◽  
pp. 4991-5001 ◽  
Author(s):  
E. Di Lullo ◽  
C. Haton ◽  
C. Le Poupon ◽  
M. Volovitch ◽  
A. Joliot ◽  
...  
Keyword(s):  
Cell Migration ◽  
Neural Tube ◽  
Precursor Cell ◽  
Oligodendrocyte Precursor Cell ◽  
Oligodendrocyte Precursor

scholarly journals High-Throughput Screening Identifies miR-451 as a Pleiotropic Modulator That Suppresses Gastric Cancer Metastasis

2016 ◽  
Vol 22 (2) ◽  
pp. 136-143 ◽  
Author(s):  
Wendao You ◽  
Liang Xu ◽  
Xing Zhang ◽  
Huan Zou ◽  
Dongtao Shi ◽  
...  
Keyword(s):  
Gastric Cancer ◽  
Cell Migration ◽  
High Throughput Screening ◽  
Cancer Metastasis ◽  
Epithelial Mesenchymal Transition ◽  
Human Gastric Cancer ◽  
Mesenchymal Transition ◽  
Therapeutic Uses ◽  
Human Carcinomas ◽  
Insight Into

MicroRNAs (miRNAs) are globally dysregulated in human carcinomas. However, the specific miRNAs that mediate gastric cancer metastasis have not been identified. We identified 100 miRNAs that are dysregulated in gastric cancer and used a self-assembled cell microarray method to systematically evaluate their capacity to regulate cell migration. MiR-451, which is down-regulated in human gastric cancer samples, potently modulated multiple metastatic phenotypes including cell migration, invasion, proliferation, and epithelial-mesenchymal transition. These effects were achieved via down-regulation of the miR-451 target gene, ERK2. These findings provide new insight into the physiological effects of and potential therapeutic uses for miRNAs in gastric cancer.

scholarly journals Small GTPase Rab21 regulates cell adhesion and controls endosomal traffic of β1-integrins

2006 ◽  
Vol 173 (5) ◽  
pp. 767-780 ◽  
Author(s):  
Teijo Pellinen ◽  
Antti Arjonen ◽  
Karoliina Vuoriluoto ◽  
Katja Kallio ◽  
Jack A.M. Fransen ◽  
...  
Keyword(s):  
Cell Migration ◽  
Cell Adhesion ◽  
Small Gtpases ◽  
Small Gtpase ◽  
Rab Proteins ◽  
Mechanistic Insight ◽  
Cancer Cell Adhesion ◽  
Intracellular Compartments ◽  
First Time ◽  
Insight Into

Dynamic turnover of integrin cell adhesion molecules to and from the cell surface is central to cell migration. We report for the first time an association between integrins and Rab proteins, which are small GTPases involved in the traffic of endocytotic vesicles. Rab21 (and Rab5) associate with the cytoplasmic domains of α-integrin chains, and their expression influences the endo/exocytic traffic of integrins. This function of Rab21 is dependent on its GTP/GDP cycle and proper membrane targeting. Knock down of Rab21 impairs integrin-mediated cell adhesion and motility, whereas its overexpression stimulates cell migration and cancer cell adhesion to collagen and human bone. Finally, overexpression of Rab21 fails to induce cell adhesion via an integrin point mutant deficient in Rab21 association. These data provide mechanistic insight into how integrins are targeted to intracellular compartments and how their traffic regulates cell adhesion.

scholarly journals A Force Based Model of Individual Cell Migration With Discrete Attachment Sites and Random Switching Terms

2013 ◽  
Vol 135 (7) ◽  
Author(s):  
J. C. Dallon ◽  
Matthew Scott ◽  
W. V. Smith
Keyword(s):  
Cell Migration ◽  
Individual Cell ◽  
Cell Types ◽  
Cell Binding ◽  
Stochastic Nature ◽  
Attachment Sites ◽  
Random Switching ◽  
Cell Motion ◽  
Cellular Forces ◽  
Insight Into

A force based model of cell migration is presented which gives new insight into the importance of the dynamics of cell binding to the substrate. The main features of the model are the focus on discrete attachment dynamics, the treatment of the cellular forces as springs, and an incorporation of the stochastic nature of the attachment sites. One goal of the model is to capture the effect of the random binding and unbinding of cell attachments on global cell motion. Simulations reveal one of the most important factor influencing cell speed is the duration of the attachment to the substrate. The model captures the correct velocity and force relationships for several cell types.

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