Gonadotropin-releasing hormone (gnrh) cells arise from cranial neural crest and adenohypophyseal regions of the neural plate in the zebrafish, danio rerio

AbstractVertebrate olfactory placodes consists of a variety of neuronal populations, which are thought to have distinct embryonic origins. In the zebrafish, while ciliated sensory neurons arise from preplacodal ectoderm (PPE), previous lineage tracing studies suggest that both Gonadotropin releasing hormone 3 (Gnrh3) and microvillous sensory neurons derive from cranial neural crest (CNC). We find that the expression of Islet1/2 is restricted to Gnrh3 neurons associated with the olfactory placode. Unexpectedly, however, we find no change in Islet1/2+ cell numbers in sox10 mutant embryos, calling into question their CNC origin. Lineage reconstruction based on backtracking in time-lapse confocal datasets, and confirmed by photoconversion experiments, reveals that Gnrh3 neurons derive from the anterior/medial PPE. Similarly, all of the microvillous sensory neurons we have traced arise from preplacodal progenitors. Our results suggest that rather than originating from separate ectodermal populations, cell-type heterogeneity is generated from overlapping pools of progenitors within the preplacodal ectoderm.

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Delta signaling mediates segregation of neural crest and spinal sensory neurons from zebrafish lateral neural plate

Development ◽

10.1242/dev.127.13.2873 ◽

2000 ◽

Vol 127 (13) ◽

pp. 2873-2882 ◽

Cited By ~ 6

Author(s):

R.A. Cornell ◽

J.S. Eisen

Keyword(s):

Neural Crest ◽

Point Mutation ◽

Sensory Neurons ◽

Genetic Difference ◽

Neural Plate ◽

Cranial Neural Crest ◽

Neural Crest Development ◽

Neural Crest Derivative ◽

Trunk Neural Crest

We examined the role of Delta signaling in specification of two derivatives in zebrafish neural plate: Rohon-Beard spinal sensory neurons and neural crest. deltaA-expressing Rohon-Beard neurons are intermingled with premigratory neural crest cells in the trunk lateral neural plate. Embryos homozygous for a point mutation in deltaA, or with experimentally reduced delta signalling, have supernumerary Rohon-Beard neurons, reduced trunk-level expression of neural crest markers and lack trunk neural crest derivatives. Fin mesenchyme, a putative trunk neural crest derivative, is present in deltaA mutants, suggesting it segregates from other neural crest derivatives as early as the neural plate stage. Cranial neural crest derivatives are also present in deltaA mutants, revealing a genetic difference in regulation of trunk and cranial neural crest development.

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Faculty Opinions recommendation of A role for foxd3 and sox10 in the differentiation of gonadotropin-releasing hormone (GnRH) cells in the zebrafish Danio rerio.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.1029127.342553 ◽

2005 ◽

Author(s):

Anthony Graham

Keyword(s):

Danio Rerio ◽

Gonadotropin Releasing Hormone ◽

Releasing Hormone

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The transcription factor Sox9 is required for cranial neural crest development inXenopus

Development ◽

10.1242/dev.129.2.421 ◽

2002 ◽

Vol 129 (2) ◽

pp. 421-432 ◽

Cited By ~ 15

Author(s):

Rebecca F. Spokony ◽

Yoichiro Aoki ◽

Natasha Saint-Germain ◽

Emily Magner-Fink ◽

Jean-Pierre Saint-Jeannet

Keyword(s):

Neural Crest ◽

Cell Fate ◽

Neural Plate ◽

Cranial Neural Crest ◽

Pharyngeal Arches ◽

Skeletal Malformations ◽

Xy Sex Reversal ◽

Human Disorder ◽

Antisense Oligos ◽

Craniofacial Defects

The SOX family of transcription factors has been implicated in cell fate specification during embryogenesis. One member of this family, Sox9, has been shown to regulate both chondrogenesis and sex determination in the mouse embryo. Heterozygous mutations in Sox9 result in Campomelic Dysplasia (CD), a lethal human disorder characterized by autosomal XY sex reversal, severe skeletal malformations and several craniofacial defects. Sox9 is also expressed in neural crest progenitors but very little is known about the function of Sox9 in the neural crest. We have cloned the Xenopus homolog of the Sox9 gene. It is expressed maternally and accumulates shortly after gastrulation at the lateral edges of the neural plate, in the neural crest-forming region. As development proceeds, Sox9 expression persists in migrating cranial crest cells as they populate the pharyngeal arches. Depletion of Sox9 protein in developing embryos, using morpholino antisense oligos, causes a dramatic loss of neural crest progenitors and an expansion of the neural plate. Later during embryogenesis, morpholino-treated embryos have a specific loss or reduction of neural crest-derived skeletal elements, mimicking one aspect of the craniofacial defects observed in CD patients. We propose that Sox9 is an essential component of the regulatory pathway that leads to cranial neural crest formation.

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Cell-type heterogeneity in the early zebrafish olfactory epithelium is generated from progenitors within preplacodal ectoderm

eLife ◽

10.7554/elife.32041 ◽

2018 ◽

Vol 7 ◽

Cited By ~ 16

Author(s):

Raphaël Aguillon ◽

Julie Batut ◽

Arul Subramanian ◽

Romain Madelaine ◽

Pascale Dufourcq ◽

...

Keyword(s):

Neural Crest ◽

Sensory Neurons ◽

Olfactory Epithelium ◽

Time Lapse ◽

Gonadotropin Releasing Hormone ◽

Lineage Tracing ◽

Cranial Neural Crest ◽

Cell Type ◽

Cell Numbers ◽

Neuronal Populations

The zebrafish olfactory epithelium comprises a variety of neuronal populations, which are thought to have distinct embryonic origins. For instance, while ciliated sensory neurons arise from preplacodal ectoderm (PPE), previous lineage tracing studies suggest that both Gonadotropin releasing hormone 3 (Gnrh3) and microvillous sensory neurons derive from cranial neural crest (CNC). We find that the expression of Islet1/2 is restricted to Gnrh3 neurons associated with the olfactory epithelium. Unexpectedly, however, we find no change in Islet1/2+ cell numbers in sox10 mutant embryos, calling into question their CNC origin. Lineage reconstruction based on backtracking in time-lapse confocal datasets, and confirmed by photoconversion experiments, reveals that Gnrh3 neurons derive from the anterior PPE. Similarly, all of the microvillous sensory neurons we have traced arise from preplacodal progenitors. Our results suggest that rather than originating from separate ectodermal populations, cell-type heterogeneity is generated from overlapping pools of progenitors within the preplacodal ectoderm.

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