Neurogenic gene regulatory pathways in the sea urchin embryo

Wen-ling, Zheng; Angerer, Lynne M.; Angerer, Robert C.

doi:10.1242/dev.125989

Cited by 30 publications

(47 citation statements)

References 40 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…It is reported that SoxC cells co-express Delta (Wei et al, 2016) and that treatment with DAPT, an inhibitor of Notch signaling, or a Delta morpholino results in the formation of clusters of neurons Wei et al, 2009;Yaguchi et al, 2011). This suggests that Notch signaling occurs subsequent to the final cell division and that the division is asymmetric, at least in the distribution of molecular components.…”

Section: Discussion the Model Of Neurogenesis In The Sea Urchinmentioning

confidence: 99%

Neurogenesis in sea urchin embryos and the diversity of deuterostome neurogenic mechanisms

et al. 2015

View full text Add to dashboard Cite

A single origin to the diverse mechanisms of metazoan neurogenesis is suggested by the involvement of common signaling components and similar classes of transcription factors. However, in many forms we lack details of where neurons arise, patterns of cell division, and specific differentiation pathway components. The sea urchin larval nervous system is composed of an apical organ, which develops from neuroepithelium and functions as a central nervous system, and peripheral neurons, which differentiate in the ciliary band and project axons to the apical organ. To reveal developmental mechanisms of neurogenesis in this basal deuterostome, we developed antibodies to SoxC, SoxB2, ELAV and Brn1/2/4 and used neurons that develop at specific locations to establish a timeline for neurogenesis. Neural progenitors express, in turn, SoxB2, SoxC, and Brn1/2/4, before projecting neurites and expressing ELAV and SynB. Using pulse-chase labeling of cells with a thymidine analog to identify cells in S-phase, we establish that neurons identified by location are in their last mitotic cycle at the time of hatching, and S-phase is coincident with expression of SoxC. The number of cells expressing SoxC and differentiating as neurons is reduced in embryos injected with antisense morpholino oligonucleotides to SoxC, SoxB2 or Six3. Injection of RNA encoding SoxC into eggs does not enhance neurogenesis. In addition, inhibition of FGF receptors (SU5402) or a morpholino to FGFR1 reduces expression of SoxC. These data indicate that there are common features of neurogenesis in deuterostomes, and that sea urchins employ developmental mechanisms that are distinct from other ambulacraria.

show abstract

Section: Discussion the Model Of Neurogenesis In The Sea Urchinmentioning

confidence: 99%

Neurogenesis in sea urchin embryos and the diversity of deuterostome neurogenic mechanisms

et al. 2015

View full text Add to dashboard Cite

show abstract

“…Neural progenitors in sea urchins and sea stars are identified by expression of the transcription factor SoxC (Cheatle Jarvela et al, 2016;Garner et al, 2016;Mellott, Thisdelle, & Burke, 2017;Wei, Angerer, & Angerer, 2016;Yankura et al, 2013) ( Figure 3). The distribution of cells expressing SoxC provides an indication of the regions that are neurogenic.…”

Section: Asymmetric Division Of Neural Progenitors and Notch Signalingmentioning

confidence: 99%

Embryonic neurogenesis in echinoderms

Hinman

Burke

2018

WIREs Developmental Biology

View full text Add to dashboard Cite

The phylogenetic position of echinoderms is well suited to revealing shared features of deuterostomes that distinguish them from other bilaterians. Although echinoderm neurobiology remains understudied, genomic resources, molecular methods, and systems approaches have enabled progress in understanding mechanisms of embryonic neurogenesis. Even though the morphology of echinoderm larvae is diverse, larval nervous systems, which arise during gastrulation, have numerous similarities in their organization. Diverse neural subtypes and specialized sensory neurons have been identified and details of neuroanatomy using neuron-specific labels provide hypotheses for neural function. The early patterning of ectoderm and specification of axes has been well studied in several species and underlying gene regulatory networks have been established. The cells giving rise to central and peripheral neural components have been identified in urchins and sea stars. Neurogenesis includes typical metazoan features of asymmetric division of neural progenitors and in some cases limited proliferation of neural precursors. Delta/Notch signaling has been identified as having critical roles in regulating neural patterning and differentiation. Several transcription factors functioning in pro-neural phases of specification, neural differentiation, and sub-type specification have been identified and structural or functional components of neurons are used as differentiation markers. Several methods for altering expression in embryos have revealed aspects of a regulatory hierarchy of transcription factors in neurogenesis. Interfacing neurogenic gene regulatory networks to the networks regulating ectodermal domains and identifying the spatial and temporal inputs that pattern the larval nervous system is a major challenge that will contribute substantially to our understanding of the evolution of metazoan nervous systems. This article is categorized under: Comparative Development and Evolution > Model Systems Comparative Development and Evolution > Body Plan Evolution Early Embryonic Development > Gastrulation and Neurulation.

show abstract

“…Because apical organs are found in such diverse organisms they offer a potentially homologous metazoan neural structure that is simple enough to dissect at the GRN level. While apical organ territory patterning is relatively well studied and conserved (Range, 2014), the process of neurogenesis that directs an ectodermally derived progenitor cell to progress to a differentiated serotonergic neuron in this territory remains poorly understood in any of these taxa, although recent work has shown a role for soxc in this process (Garner et al, 2015;Wei et al, 2016).…”

Section: Introductionmentioning

confidence: 99%

A gene regulatory network for apical organ neurogenesis and its spatial control in sea star embryos

2016

View full text Add to dashboard Cite

How neural stem cells generate the correct number and type of differentiated neurons in appropriate places remains an important question. Although nervous systems are diverse across phyla, in many taxa the larva forms an anterior concentration of serotonergic neurons, or apical organ. The sea star embryo initially has a panneurogenic ectoderm, but the genetic mechanism that directs a subset of these cells to generate serotonergic neurons in a particular location is unresolved. We show that neurogenesis in sea star larvae begins with soxc-expressing multipotent progenitors. These give rise to restricted progenitors that express lhx2/9. soxc-and lhx2/9-expressing cells can undergo both asymmetric divisions, allowing for progression towards a particular neural fate, and symmetric proliferative divisions. We show that nested concentric domains of gene expression along the anterior-posterior (AP) axis, which are observed in a great diversity of metazoans, control neurogenesis in the sea star larva by promoting particular division modes and progression towards becoming a neuron. This work explains how spatial patterning in the ectoderm controls progression of neurogenesis in addition to providing spatial cues for neuron location. Modification to the sizes of these AP territories provides a simple mechanism to explain the diversity of neuron number among apical organs.

show abstract

Neurogenic gene regulatory pathways in the sea urchin embryo

Cited by 30 publications

References 40 publications

Neurogenesis in sea urchin embryos and the diversity of deuterostome neurogenic mechanisms

Neurogenesis in sea urchin embryos and the diversity of deuterostome neurogenic mechanisms

Embryonic neurogenesis in echinoderms

A gene regulatory network for apical organ neurogenesis and its spatial control in sea star embryos

Contact Info

Product

Resources

About