Pax3 is required for cardiac neural crest migration in the mouse: evidence from the splotch (Sp2H) mutant

Development ◽  
1997 ◽  
Vol 124 (2) ◽  
pp. 505-514 ◽  
Author(s):  
S.J. Conway ◽  
D.J. Henderson ◽  
A.J. Copp

Neural crest cells originating in the occipital region of the avian embryo are known to play a vital role in formation of the septum of the cardiac outflow tract and to contribute cells to the aortic arches, thymus, thyroid and parathyroids. This ‘cardiac’ neural crest sub-population is assumed to exist in mammals, but without direct evidence. In this paper we demonstrate, using RT-PCR and in situ hybridisation, that Pax3 expression can serve as a marker of cardiac neural crest cells in the mouse embryo. Cells of this lineage were traced from the occipital neural tube, via branchial arches 3, 4 and 6, into the aortic sac and aorto-pulmonary outflow tract. Confirmation that these Pax3-positive cells are indeed cardiac neural crest is provided by experiments in which hearts were deprived of a source of colonising neural crest, by organ culture in vitro, with consequent lack of up-regulation of Pax3. Occipital neural crest cell outgrowths in vitro were also shown to express Pax3. Mutation of Pax3, as occurs in the splotch (Sp2H) mouse, results in development of conotruncal heart defects including persistent truncus arteriosus. Homozygotes also exhibit defects of the aortic arches, thymus, thyroid and parathyroids. Pax3-positive neural crest cells were found to emigrate from the occipital neural tube of Sp2H/Sp2H embryos in a relatively normal fashion, but there was a marked deficiency or absence of neural crest cells traversing branchial arches 3, 4 and 6, and entering the cardiac outflow tract. This decreased expression of Pax3 in Sp2H/Sp2H embryos was not due to down-regulation of Pax3 in neural crest cells, as use of independent neural crest markers, Hoxa-3, CrabpI, Prx1, Prx2 and c-met also revealed a deficiency of migrating cardiac neural crest cells in homozygous embryos. This work demonstrates the essential role of the cardiac neural crest in formation of the heart and great vessels in the mouse and, furthermore, shows that Pax3 function is required for the cardiac neural crest to complete its migration to the developing heart.

1998 ◽  
Vol 196 (2) ◽  
pp. 129-144 ◽  
Author(s):  
Karen Waldo ◽  
Sachiko Miyagawa-Tomita ◽  
Donna Kumiski ◽  
Margaret L. Kirby

Development ◽  
2000 ◽  
Vol 127 (9) ◽  
pp. 1869-1878 ◽  
Author(s):  
J.A. Epstein ◽  
J. Li ◽  
D. Lang ◽  
F. Chen ◽  
C.B. Brown ◽  
...  

Pax3 encodes a transcription factor expressed during mid-gestation in the region of the dorsal neural tube that gives rise to migrating neural crest populations. In the absence of Pax3, both humans and mice develop with neural crest defects. Homozygous Splotch embryos that lack Pax3 die by embryonic day 13.5 with cardiac defects that resemble those induced by neural crest ablation in chick models. This has led to the hypothesis that Pax3 is required for cardiac neural crest migration. However, cardiac derivatives of Pax3-expressing precursor cells have not been previously defined, and Pax3-expressing cells within the heart have not been well demonstrated. Hence, the precise role of Pax3 during cardiac development remains unclear. Here, we use a Cre-lox method to fate map Pax3-expressing neural crest precursors to the cardiac outflow tract. We show that although Pax3 itself is extinguished prior to neural crest populating the heart, derivatives of these precursors contribute to the aorticopulmonary septum. We further show that neural crest cells are found in the outflow tract of Splotch embryos, albeit in reduced numbers. This indicates that contrary to prior reports, Pax3 is not required for cardiac neural crest migration. Using a neural tube explant culture assay, we demonstrate that neural crest cells from Splotch embryos show normal rates of proliferation but altered migratory characteristics. These studies suggest that Pax3 is required for fine tuning the migratory behavior of the cardiac neural crest cells while it is not essential for neural crest migration.


2020 ◽  
Vol 7 (2) ◽  
pp. 13
Author(s):  
Joshua W. Vincentz ◽  
David E. Clouthier ◽  
Anthony B. Firulli

Congenital heart defects (CHDs) occur with such a frequency that they constitute a significant cause of morbidity and mortality in both children and adults. A significant portion of CHDs can be attributed to aberrant development of the cardiac outflow tract (OFT), and of one of its cellular progenitors known as the cardiac neural crest cells (NCCs). The gene regulatory networks that identify cardiac NCCs as a distinct NCC population are not completely understood. Heart and neural crest derivatives (HAND) bHLH transcription factors play essential roles in NCC morphogenesis. The Hand1PA/OFT enhancer is dependent upon bone morphogenic protein (BMP) signaling in both cranial and cardiac NCCs. The Hand1PA/OFT enhancer is directly repressed by the endothelin-induced transcription factors DLX5 and DLX6 in cranial but not cardiac NCCs. This transcriptional distinction offers the unique opportunity to interrogate NCC specification, and to understand why, despite similarities, cranial NCC fate determination is so diverse. We generated a conditionally active transgene that can ectopically express DLX5 within the developing mouse embryo in a Cre-recombinase-dependent manner. Ectopic DLX5 expression represses cranial NCC Hand1PA/OFT-lacZ reporter expression more effectively than cardiac NCC reporter expression. Ectopic DLX5 expression induces broad domains of NCC cell death within the cranial pharyngeal arches, but minimal cell death in cardiac NCC populations. This study shows that transcription control of NCC gene regulatory programs is influenced by their initial specification at the dorsal neural tube.


2007 ◽  
Vol 27 (1) ◽  
pp. 45-52
Author(s):  
Koh-ichi Atoh ◽  
Manae S. Kurokawa ◽  
Hideshi Yoshikawa ◽  
Chieko Masuda ◽  
Erika Takada ◽  
...  

Development ◽  
1990 ◽  
Vol 108 (4) ◽  
pp. 543-558 ◽  
Author(s):  
G. Couly ◽  
N.M. Le Douarin

Areas of the superficial cephalic ectoderm, including or excluding the neural fold at the same level, were surgically removed from 3-somite chick embryos and replaced by their counterparts excised from a quail embryo at the same developmental stage. Strips of ectoderm corresponding to the presumptive branchial arches were delineated, thus defining anteroposterior ‘segments’ (designated here as ‘ectomeres’) that coincided with the spatial distribution of neural crest cells arising from the adjacent levels of the neural fold. This discrete ectodermal metamerisation parallels the segmentation of the hindbrain into rhombomeres. It seems, therefore, that not only is the neural crest patterned according to its rhombomeric origin but that the superficial ectoderm covering the branchial arches may be part of a larger developmental unit that includes the entire neurectoderm, i.e., the neural tube and the neural crest.


Development ◽  
1991 ◽  
Vol 112 (4) ◽  
pp. 913-920 ◽  
Author(s):  
S.E. Fraser ◽  
M. Bronner-Fraser

Trunk neural crest cells migrate extensively and give rise to diverse cell types, including cells of the sensory and autonomic nervous systems. Previously, we demonstrated that many premigratory trunk neural crest cells give rise to descendants with distinct phenotypes in multiple neural crest derivatives. The results are consistent with the idea that neural crest cells are multipotent prior to their emigration from the neural tube and become restricted in phenotype after leaving the neural tube either during their migration or at their sites of localization. Here, we test the developmental potential of migrating trunk neural crest cells by microinjecting a vital dye, lysinated rhodamine dextran (LRD), into individual cells as they migrate through the somite. By two days after injection, the LRD-labelled clones contained from 2 to 67 cells, which were distributed unilaterally in all embryos. Most clones were confined to a single segment, though a few contributed to sympathetic ganglia over two segments. A majority of the clones gave rise to cells in multiple neural crest derivatives. Individual migrating neural crest cells gave rise to both sensory and sympathetic neurons (neurofilament-positive), as well as cells with the morphological characteristics of Schwann cells, and other non-neuronal cells (both neurofilament-negative). Even those clones contributing to only one neural crest derivative often contained both neurofilament-positive and neurofilament-negative cells. Our data demonstrate that migrating trunk neural crest cells can be multipotent, giving rise to cells in multiple neural crest derivatives, and contributing to both neuronal and non-neuronal elements within a given derivative.(ABSTRACT TRUNCATED AT 250 WORDS)


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.


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