scholarly journals The role of the rhombic lip in avian cerebellum development

Development ◽  
1999 ◽  
Vol 126 (20) ◽  
pp. 4395-4404 ◽  
Author(s):  
R.J. Wingate ◽  
M.E. Hatten
Keyword(s):  
Axon Guidance ◽  
Granule Cell ◽  
Fate Mapping ◽  
Germinal Layer ◽  
Pontine Nucleus ◽  
Dorsoventral Axis ◽  
Cerebellum Development ◽  
Mapping Techniques ◽  
Rhombic Lip

We have used a combination of quail-chick fate-mapping techniques and dye labelling to investigate the development of the avian cerebellum. Using Hoxa2 as a guide for the microsurgical construction of quail-chick chimaeras, we show that the caudal boundary of the presumptive cerebellum at E6 maps to the caudal boundary of rhombomere 1. By fate mapping the dorsoventral axis of rhombomere 1, we demonstrate that granule cell precursors are generated at the rhombic lip together with neurons of the lateral pontine nucleus. DiI-labelling of cerebellum explants reveals that external germinal layer precursors have a characteristic unipolar morphology and undergo an orientated, active migration away from the rhombic lip, which is apparently independent of either glial or axon guidance or ‘chain’ formation.

Role of Pax6 in development of the cerebellar system

Development ◽  
1999 ◽  
Vol 126 (16) ◽  
pp. 3585-3596 ◽  
Author(s):  
D. Engelkamp ◽  
P. Rashbass ◽  
A. Seawright ◽  
V. van Heyningen
Keyword(s):  
Cell Proliferation ◽  
Cell Migration ◽  
Granule Cell ◽  
Granule Cells ◽  
Cerebellar Granule Cells ◽  
Long Distance ◽  
Cerebellar Granule ◽  
Precerebellar Nuclei ◽  
Rhombic Lip

Post-mitotic neurons generated at the rhombic lip undertake long distance migration to widely dispersed destinations, giving rise to cerebellar granule cells and the precerebellar nuclei. Here we show that Pax6, a key regulator in CNS and eye development, is strongly expressed in rhombic lip and in cells migrating away from it. Development of some structures derived from these cells is severely affected in Pax6-null Small eye (Pax6(Sey)/Pax6(Sey)) embryos. Cell proliferation and initial differentiation seem unaffected, but cell migration and neurite extension are disrupted in mutant embryos. Three of the five precerebellar nuclei fail to form correctly. In the cerebellum the pre-migratory granule cell sub-layer and fissures are absent. Some granule cells are found in ectopic positions in the inferior colliculus which may result from the complete absence of Unc5h3 expression in Pax6(Sey)/Pax6(Sey) granule cells. Our results suggest that Pax6 plays a strong role during hindbrain migration processes and at least part of its activity is mediated through regulation of the netrin receptor Unc5h3.

Embryonic phenotype of Unc5h3 mutant mice suggests chemorepulsion during the formation of the rostral cerebellar boundary

Development ◽  
1998 ◽  
Vol 125 (1) ◽  
pp. 41-50 ◽  
Author(s):  
S.A. Przyborski ◽  
B.B. Knowles ◽  
S.L. Ackerman
Keyword(s):  
Purkinje Cell ◽  
Granule Cell ◽  
Neuronal Migration ◽  
Granule Neurons ◽  
Wild Type ◽  
Germinal Layer ◽  
Proliferation Markers ◽  
Guidance Molecule ◽  
Rhombic Lip ◽  
Cerebellar Cells

Mutation of the Unc5h3 (formally known as rcm) gene has important consequences on neuronal migration during cerebellar development. Unc5h3 transcripts are expressed early (embryonic day 8.5) in the hindbrain region and later in the cerebellar primordia. In Unc5h3 mutant embryos, both the development and initial migration of Purkinje cell progenitors occur as in wild-type controls. The rhombic lip, from which granule cell precursors arise, also appears to form normally in mutants. However, at E13.5, an abnormal subpopulation of granule cell and Purkinje cell precursors becomes detectable in rostral areas of the Unc5h3 mutant brain stem. These ectopic cerebellar cells increase in number and continue moving in a rostral direction throughout the remainder of embryogenesis and early stages of postnatal development invading the lateral regions of the pontine area and eventually the inferior colliculus. Cell proliferation markers demonstrate the mitotic nature of these subpial ectopic granule neurons indicating the displacement of the rostral external germinal layer in mutant animals. Our data suggest that establishment of the rostral cerebellar boundary may rely on chemorepulsive signaling events that require UNC5H3 expressed by cerebellar neurons and extracellular ligands that are functionally related to the UNC5H3-binding, guidance molecule netrin1. Although the phenotype resulting from the Unc5h3 mutation is apparently limited to the formation of the cerebellum, additional sites of Unc5h3 expression are also found during development suggesting the compensatory function of other genes.

Role of PACAP in Controlling Granule Cell Migration

2009 ◽  
Vol 8 (4) ◽  
pp. 433-440 ◽  
Author(s):  
Donald Bryant Cameron ◽  
Emilie Raoult ◽  
Ludovic Galas ◽  
Yulan Jiang ◽  
Kimberly Lee ◽  
...  
Keyword(s):  
Cell Migration ◽  
Granule Cell

scholarly journals Intraoperative neurophysiological mapping and monitoring in spinal tumor surgery: sirens or indispensable tools?

2016 ◽  
Vol 41 (2) ◽  
pp. E18 ◽  
Author(s):  
Antonino Scibilia ◽  
Carmen Terranova ◽  
Vincenzo Rizzo ◽  
Giovanni Raffa ◽  
Adolfo Morelli ◽  
...  
Keyword(s):  
Complex Function ◽  
Spinal Tumor ◽  
Neurological Deficits ◽  
Neurological Injury ◽  
Neurophysiological Monitoring ◽  
Predictive Values ◽  
Effective Role ◽  
Mapping Techniques ◽  
Sensitivity Specificity

Spinal tumor (ST) surgery carries the risk of new neurological deficits in the postoperative period. Intraoperative neurophysiological monitoring and mapping (IONM) represents an effective method of identifying and monitoring in real time the functional integrity of both the spinal cord (SC) and the nerve roots (NRs). Despite consensus favoring the use of IONM in ST surgery, in this era of evidence-based medicine, there is still a need to demonstrate the effective role of IONM in ST surgery in achieving an oncological cure, optimizing patient safety, and considering medicolegal aspects. Thus, neurosurgeons are asked to establish which techniques are considered indispensable. In the present study, the authors focused on the rationale for and the accuracy (sensitivity, specificity, and positive and negative predictive values) of IONM in ST surgery in light of more recent evidence in the literature, with specific emphasis on the role of IONM in reducing the incidence of postoperative neurological deficits. This review confirms the role of IONM as a useful tool in the workup for ST surgery. Individual monitoring and mapping techniques are clearly not sufficient to account for the complex function of the SC and NRs. Conversely, multimodal IONM is highly sensitive and specific for anticipating neurological injury during ST surgery and represents an important tool for preserving neuronal structures and achieving an optimal postoperative functional outcome.

The Role of Galanin in Cerebellar Granule Cell Migration in the Early Postnatal Mouse during Normal Development and After Injury

2021 ◽  
pp. JN-RM-0900-15
Author(s):  
Yutaro Komuro ◽  
Ludovic Galas ◽  
Yury M. Morozov ◽  
Jennifer K. Fahrion ◽  
Emilie Raoult ◽  
...  
Keyword(s):  
Cell Migration ◽  
Granule Cell ◽  
Normal Development ◽  
Cerebellar Granule Cell ◽  
Cerebellar Granule

Frazzled/Dcc acts independently of Netrin to promote germline survival during Drosophila oogenesis

Development ◽  
2021 ◽  
Vol 148 (24) ◽  
Author(s):  
Samantha A. Russell ◽  
Kaitlin M. Laws ◽  
Greg J. Bashaw
Keyword(s):  
Cell Death ◽  
Axon Guidance ◽  
Transcriptional Activation ◽  
Nutrient Sensing ◽  
Activation Domain ◽  
Transcriptional Activation Domain ◽  
Egg Chambers ◽  
Death Effector ◽  
Female Germline

ABSTRACT The Netrin receptor Frazzled/Dcc (Fra in Drosophila) functions in diverse tissue contexts to regulate cell migration, axon guidance and cell survival. Fra signals in response to Netrin to regulate the cytoskeleton and also acts independently of Netrin to directly regulate transcription during axon guidance in Drosophila. In other contexts, Dcc acts as a tumor suppressor by directly promoting apoptosis. In this study, we report that Fra is required in the Drosophila female germline for the progression of egg chambers through mid-oogenesis. Loss of Fra in the germline, but not the somatic cells of the ovary, results in the degeneration of egg chambers. Although a failure in nutrient sensing and disruptions in egg chamber polarity can result in degeneration at mid-oogenesis, these factors do not appear to be affected in fra germline mutants. However, similar to the degeneration that occurs in those contexts, the cell death effector Dcp-1 is activated in fra germline mutants. The function of Fra in the female germline is independent of Netrin and requires the transcriptional activation domain of Fra. In contrast to the role of Dcc in promoting cell death, our observations reveal a role for Fra in regulating germline survival by inhibiting apoptosis.

scholarly journals The specification of noradrenergic locus coeruleus (LC) neurones depends on bone morphogenetic proteins (BMPs)

Development ◽  
2002 ◽  
Vol 129 (4) ◽  
pp. 983-991 ◽  
Author(s):  
Astrid Vogel-Höpker ◽  
Hermann Rohrer
Keyword(s):  
Transcription Factors ◽  
Locus Coeruleus ◽  
Bone Morphogenetic Proteins ◽  
Chick Embryos ◽  
Dorsal Midline ◽  
Neural Crest Development ◽  
Roof Plate ◽  
Rhombic Lip ◽  
The Brain

The role of BMPs in the development of the major noradrenergic centre of the brain, the locus coeruleus (LC), was investigated. LC generation is reflected by initial expression of the transcription factors Phox2a and Phox2b in dorsal rhombomere1 (r1), followed by expression of dopamine-β-hydroxylase and tyrosine hydroxylase. Bmp5 is expressed in the dorsal neuroepithelium in proximity to Phox2-expressing cells. BMP inhibition in stage 10 chick embryos resulted in the lack of LC neurones or in their generation at the dorsal midline, and loss of roof plate and rhombic lip, but it did not affect neural crest development. These results reveal late essential BMP functions in the specification of dorsal neuronal phenotypes in r1, including LC neurones, and in the development of dorsal midline structures.

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