scholarly journals Neural crest cell-cell adhesion controlled by sequential and subpopulation-specific expression of novel cadherins

Development ◽  
1995 ◽  
Vol 121 (5) ◽  
pp. 1321-1332 ◽  
Author(s):  
S. Nakagawa ◽  
M. Takeichi

We identified two cadherins, c-cad6B and c-cad7, expressed by neural crest cells at their premigratory and migratory stages, respectively, in chicken embryos. cDNA transfection experiments showed that both were homophilic adhesion molecules, endowing cells with specific adhesiveness. During development, c-cad6B appeared in the neural fold, localizing at the future neural crest area. This expression was maintained during neural tube closure, but disappeared after neural crest cells had left the neural tube, suggesting its role in neural fold fusion and/or in the formation and maintenance of the presumptive neural crest domain in the neural plate/tube. Crest cells emerging from the neural tube lost c-cad6B, and a subpopulation of them began to express c-cad7. This subpopulation-specific expression of c-cad7 persisted during their migration. The migrating c-cad7-positive cells clustered together, and eventually populated restricted regions including the dorsal and ventral roots but very little ganglia. The latter was populated with N-cadherin-positive crest cells. Migrating neural crest cells expressed alpha- and beta-catenin at cell-cell contacts, indicating that their cadherins are functioning. These results suggest that the migrating crest cells are grouped into subpopulations expressing different cadherins. The cadherin-mediated specific interaction between crest cells likely plays a role in intercellular signaling between homotypic cells as well as in sorting of heterotypic cells.

Development ◽  
1989 ◽  
Vol 106 (4) ◽  
pp. 787-798
Author(s):  
G. Morriss-Kay ◽  
F. Tuckett

Studies on cell behaviour in vitro have indicated that the chondroitin sulphate proteoglycan (CSPG) family of molecules can participate in the control of cell proliferation, differentiation and adhesion, but its morphogenetic functions had not been investigated in intact embryos. Chondroitin/chondroitin sulphates have been identified in rat embryos at low levels at the start of neurulation (day 9) and at much higher levels on day 10. In this study we have sought evidence for the morphogenetic functions of CSPGs in rat embryos during the period of neurulation and neural crest cell migration by a combination of two approaches: immunocytochemical localization of CSPG by means of an antibody, CS-56, to the chondroitin sulphate component of CSPG, and exposure of embryos to the enzyme chondroitinase ABC. Staining of the CS-56 epitope was poor at the beginning of cranial neurulation; bright staining was at first confined to the primary mesenchyme under the convex neural folds late on day 9. In day 10 embryos, all mesenchyme cells were stained, but at different levels of intensity, so that primary mesenchyme, neural crest and sclerotomal cells could be distinguished from each other. Basement membranes were also stained, particularly bright staining being present where two epithelial were basally apposed, e.g., neural/surface ectoderms, dorsal aorta/neural tube, prior to migration of a population of cells between them. Staining within the neural epithelium was first confined to the dorsolateral edge region, and associated with the onset of neural crest cell emigration; after neural tube closure, neuroepithelial staining was more general. Neural crest cells were stained during migration, but the reaction was absent in areas associated with migration end-points (trigeminal ganglion anlagen, frontonasal mesenchyme). Embryos exposed to chondroitinase ABC in culture showed no abnormalities until early day 10, when cranial neural crest cell emigration from the neural epithelium was inhibited and neural tube closure was retarded. Sclerotomal cells failed to take their normal pathway between the dorsal aorta and neural tube. Correlation of the results of these two methods suggests: (1) that by decreasing adhesiveness within the neural epithelium at specific stages, CSPG facilitates the emigration of neural crest cells and the migratory movement of neuroblasts, and may also provide increased flexibility during the generation of epithelial curvatures; (2) that by decreasing the adhesiveness of fibronectin-containing extracellular matrices, CSPG facilitates the migration of neural crest and sclerotomal cells. This second function is particularly important when migrating cells take pathways between previously apposed tissues.


Development ◽  
2000 ◽  
Vol 127 (13) ◽  
pp. 2843-2852 ◽  
Author(s):  
P. Kulesa ◽  
M. Bronner-Fraser ◽  
S. Fraser

Previous analyses of single neural crest cell trajectories have suggested important roles for interactions between neural crest cells and the environment, and amongst neural crest cells. To test the relative contribution of intrinsic versus extrinsic information in guiding cells to their appropriate sites, we ablated subpopulations of premigratory chick hindbrain neural crest and followed the remaining neural crest cells over time using a new in ovo imaging technique. Neural crest cell migratory behaviors are dramatically different in ablated compared with unoperated embryos. Deviations from normal migration appear either shortly after cells emerge from the neural tube or en route to the branchial arches, areas where cell-cell interactions typically occur between neural crest cells in normal embryos. Unlike the persistent, directed trajectories in normal embryos, neural crest cells frequently change direction and move somewhat chaotically after ablation. In addition, the migration of neural crest cells in collective chains, commonly observed in normal embryos, was severely disrupted. Hindbrain neural crest cells have the capacity to reroute their migratory pathways and thus compensate for missing neural crest cells after ablation of neighboring populations. Because the alterations in neural crest cell migration are most dramatic in regions that would normally foster cell-cell interactions, the trajectories reported here argue that cell-cell interactions have a key role in the shaping of the neural crest migration.


Development ◽  
1995 ◽  
Vol 121 (2) ◽  
pp. 525-538 ◽  
Author(s):  
M.A. Selleck ◽  
M. Bronner-Fraser

We have investigated the lineage and tissue interactions that result in avian neural crest cell formation from the ectoderm. Presumptive neural plate was grafted adjacent to non-neural ectoderm in whole embryo culture to examine the role of tissue interactions in ontogeny of the neural crest. Our results show that juxtaposition of non-neural ectoderm and presumptive neural plate induces the formation of neural crest cells. Quail/chick recombinations demonstrate that both the prospective neural plate and the prospective epidermis can contribute to the neural crest. When similar neural plate/epidermal confrontations are performed in tissue culture to look at the formation of neural crest derivatives, juxtaposition of epidermis with either early (stages 4–5) or later (stages 6–10) neural plate results in the generation of both melanocytes and sympathoadrenal cells. Interestingly, neural plates isolated from early stages form no neural crest cells, whereas those isolated later give rise to melanocytes but not crest-derived sympathoadrenal cells. Single cell lineage analysis was performed to determine the time at which the neural crest lineage diverges from the epidermal lineage and to elucidate the timing of neural plate/epidermis interactions during normal development. Our results from stage 8 to 10+ embryos show that the neural plate/neural crest lineage segregates from the epidermis around the time of neural tube closure, suggesting that neural induction is still underway at open neural plate stages.


Development ◽  
1989 ◽  
Vol 106 (4) ◽  
pp. 809-816 ◽  
Author(s):  
G.N. Serbedzija ◽  
M. Bronner-Fraser ◽  
S.E. Fraser

To permit a more detailed analysis of neural crest cell migratory pathways in the chick embryo, neural crest cells were labelled with a nondeleterious membrane intercalating vital dye, DiI. All neural tube cells with endfeet in contact with the lumen, including premigratory neural crest cells, were labelled by pressure injecting a solution of DiI into the lumen of the neural tube. When assayed one to three days later, migrating neural crest cells, motor axons, and ventral root cells were the only cells types external to the neural tube labelled with DiI. During the neural crest cell migratory phase, distinctly labelled cells were found along: (1) a dorsolateral pathway, under the epidermis, as well adjacent to and intercalating through the dermamyotome; and (2) a ventral pathway, through the rostral portion of each sclerotome and around the dorsal aorta as described previously. In contrast to those cells migrating through the sclerotome, labelled cells on the dorsolateral pathway were not segmentally arranged along the rostrocaudal axis. DiI-labelled cells were observed in all truncal neural crest derivatives, including subepidermal presumptive pigment cells, dorsal root ganglia, and sympathetic ganglia. By varying the stage at which the injection was performed, neural crest cell emigration at the level of the wing bud was shown to occur from stage 13 through stage 22. In addition, neural crest cells were found to populate their derivatives in a ventral-to-dorsal order, with the latest emigrating cells migrating exclusively along the dorsolateral pathway.


Development ◽  
1988 ◽  
Vol 103 (4) ◽  
pp. 743-756 ◽  
Author(s):  
H.H. Epperlein ◽  
W. Halfter ◽  
R.P. Tucker

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)


Development ◽  
2000 ◽  
Vol 127 (6) ◽  
pp. 1161-1172 ◽  
Author(s):  
P.M. Kulesa ◽  
S.E. Fraser

Hindbrain neural crest cells were labeled with DiI and followed in ovo using a new approach for long-term time-lapse confocal microscopy. In ovo imaging allowed us to visualize neural crest cell migration 2–3 times longer than in whole embryo explant cultures, providing a more complete picture of the dynamics of cell migration from emergence at the dorsal midline to entry into the branchial arches. There were aspects of the in ovo neural crest cell migration patterning which were new and different. Surprisingly, there was contact between neural crest cell migration streams bound for different branchial arches. This cell-cell contact occurred in the region lateral to the otic vesicle, where neural crest cells within the distinct streams diverted from their migration pathways into the branchial arches and instead migrated around the otic vesicle to establish a contact between streams. Some individual neural crest cells did appear to cross between the streams, but there was no widespread mixing. Analysis of individual cell trajectories showed that neural crest cells emerge from all rhombomeres (r) and sort into distinct exiting streams adjacent to the even-numbered rhombomeres. Neural crest cell migration behaviors resembled the wide diversity seen in whole embryo chick explants, including chain-like cell arrangements; however, average in ovo cell speeds are as much as 70% faster. To test to what extent neural crest cells from adjoining rhombomeres mix along migration routes and within the branchial arches, separate groups of premigratory neural crest cells were labeled with DiI or DiD. Results showed that r6 and r7 neural crest cells migrated to the same spatial location within the fourth branchial arch. The diversity of migration behaviors suggests that no single mechanism guides in ovo hindbrain neural crest cell migration into the branchial arches. The cell-cell contact between migration streams and the co-localization of neural crest cells from adjoining rhombomeres within a single branchial arch support the notion that the pattern of hindbrain neural crest cell migration emerges dynamically with cell-cell communication playing an important guidance role.


Development ◽  
1998 ◽  
Vol 125 (24) ◽  
pp. 4919-4930 ◽  
Author(s):  
M.A. Selleck ◽  
M.I. Garcia-Castro ◽  
K.B. Artinger ◽  
M. Bronner-Fraser

To define the timing of neural crest formation, we challenged the fate of presumptive neural crest cells by grafting notochords, Sonic Hedgehog- (Shh) or Noggin-secreting cells at different stages of neurulation in chick embryos. Notochords or Shh-secreting cells are able to prevent neural crest formation at open neural plate levels, as assayed by DiI-labeling and expression of the transcription factor, Slug, suggesting that neural crest cells are not committed to their fate at this time. In contrast, the BMP signaling antagonist, Noggin, does not repress neural crest formation at the open neural plate stage, but does so if injected into the lumen of the closing neural tube. The period of Noggin sensitivity corresponds to the time when BMPs are expressed in the dorsal neural tube but are down-regulated in the non-neural ectoderm. To confirm the timing of neural crest formation, Shh or Noggin were added to neural folds at defined times in culture. Shh inhibits neural crest production at early stages (0-5 hours in culture), whereas Noggin exerts an effect on neural crest production only later (5-10 hours in culture). Our results suggest three phases of neurulation that relate to neural crest formation: (1) an initial BMP-independent phase that can be prevented by Shh-mediated signals from the notochord; (2) an intermediate BMP-dependent phase around the time of neural tube closure, when BMP-4 is expressed in the dorsal neural tube; and (3) a later pre-migratory phase which is refractory to exogenous Shh and Noggin.


Development ◽  
1993 ◽  
Vol 118 (2) ◽  
pp. 363-376 ◽  
Author(s):  
A. Collazo ◽  
M. Bronner-Fraser ◽  
S.E. Fraser

Although the Xenopus embryo has served as an important model system for both molecular and cellular studies of vertebrate development, comparatively little is known about its neural crest. Here, we take advantage of the ease of manipulation and relative transparency of Xenopus laevis embryos to follow neural crest cell migration and differentiation in living embryos. We use two techniques to study the lineage and migratory patterns of frog neural crest cells: (1) injections of DiI or lysinated rhodamine dextran (LRD) into small populations of neural crest cells to follow movement and (2) injections of LRD into single cells to follow cell lineage. By using non-invasive approaches that allow observations in living embryos and control of the time and position of labelling, we have been able to expand upon the results of previous grafting experiments. Migration and differentiation of the labelled cells were observed over time in individual living embryos, and later in sections to determine precise position and morphology. Derivatives populated by the neural crest are the fins, pigment stripes, spinal ganglia, adrenal medulla, pronephric duct, enteric nuclei and the posterior portion of the dorsal aorta. In the rostral to mid-trunk levels, most neural crest cells migrate along two paths: a dorsal pathway into the fin, followed by presumptive fin cells, and a ventral pathway along the neural tube and notochord, followed by presumptive pigment, sensory ganglion, sympathetic ganglion and adrenal medullary cells. In the caudal trunk, two additional paths were noted. One group of cells moves circumferentially within the fin, in an arc from dorsal to ventral; another progresses ventrally to the anus and subsequently populates the ventral fin. By labelling individual precursor cells, we find that neural tube and neural crest cells often share a common precursor. The majority of clones contain labelled progeny cells in the dorsal fin. The remainder have progeny in multiple derivatives including spinal ganglion cells, pigment cells, enteric cells, fin cells and/or neural tube cells in all combinations, suggesting that many premigratory Xenopus neural crest precursors are multipotent.


Development ◽  
1995 ◽  
Vol 121 (4) ◽  
pp. 935-945 ◽  
Author(s):  
E. Birgbauer ◽  
J. Sechrist ◽  
M. Bronner-Fraser ◽  
S. Fraser

Neural crest cell migration in the hindbrain is segmental, with prominent streams of migrating cells adjacent to rhombomeres (r) r2, r4 and r6, but not r3 or r5. This migratory pattern cannot be explained by the failure of r3 and r5 to produce neural crest, since focal injections of the lipophilic dye, DiI, into the neural folds clearly demonstrate that all rhombomeres produce neural crest cells. Here, we examine the dynamics of hindbrain neural crest cell emigration and movement by iontophoretically injecting DiI into small numbers of cells. The intensely labeled cells and their progeny were repeatedly imaged using low-light-level epifluorescence microscopy, permitting their movement to be followed in living embryos over time. These intravital images definitively show that neural crest cells move both rostrally and caudally from r3 and r5 to emerge as a part of the streams adjacent to r2, r4, and/or r6. Within the first few hours, cells labeled in r3 move within and/or along the dorsal neural tube surface, either rostrally toward the r2/3 border or caudally toward the r3/4 border. The labeled cells exit the surface of the neural tube near these borders and migrate toward the first or second branchial arches several hours after initial labeling. Focal DiI injections into r5 resulted in neural crest cell contributions to both the second and third branchial arches, again via rostrocaudal movements of the cells before migration into the periphery. These results demonstrate conclusively that all rhombomeres give rise to neural crest cells, and that rostrocaudal rearrangement of the cells contributes to the segmental migration of neural crest cells adjacent to r2, r4, and r6. Furthermore, it appears that there are consistent exit points of neural crest cell emigration; for example, cells arising from r3 emigrate almost exclusively from the rostral or caudal borders of that rhombomere.


Development ◽  
1999 ◽  
Vol 126 (11) ◽  
pp. 2495-2503 ◽  
Author(s):  
J. Li ◽  
K.C. Liu ◽  
F. Jin ◽  
M.M. Lu ◽  
J.A. Epstein

Pax3-deficient Splotch mice display neural tube defects and an array of neural crest related abnormalities including defects in the cardiac outflow tract, dorsal root ganglia and pigmentation. Pax3 is expressed in neural crest cells that emerge from the dorsal neural tube. Pax3 is also expressed in the somites, through which neural crest cells migrate, where it is required for hypaxial muscle development. Homozygous mutant Splotch embryos die by embryonic day 14. We have utilized the proximal 1.6 kb Pax3 promoter and upstream regulatory elements to engineer transgenic mice reproducing endogenous Pax3 expression in neural tube and neural crest, but not the somite. Over expression of Pax3 in these tissues reveals no discernible phenotype. Breeding of transgenic mice onto a Splotch background demonstrates that neural tube and neural crest expression of Pax3 is sufficient to rescue neural tube closure, cardiac development and other neural crest related defects. Transgenic Splotch mice survive until birth at which time they succumb to respiratory failure secondary to absence of a muscular diaphragm. Limb muscles are also absent. These results indicate that regulatory elements sufficient for functional expression of Pax3 required for cardiac development and neural tube closure are contained within the region 1.6 kb upstream of the Pax3 transcriptional start site. In addition, the single Pax3 isoform used for this transgene is sufficient to execute these developmental processes. Although the extracellular matrix and the environment of the somites through which neural crest migrates is known to influence neural crest behavior, our results indicate that Pax3-deficient somites are capable of supporting proper neural crest migration and function suggesting a cell autonomous role for Pax3 in neural crest.


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