scholarly journals Cerebellar granule cell precursors can extend processes, undergo short migratory movements and express postmitotic markers before mitosis in the chick EGL

2017 ◽  
Author(s):  
Michalina Hanzel ◽  
Richard JT Wingate
Keyword(s):  
Granule Cell ◽  
Granule Cells ◽  
Cerebellar Granule Cells ◽  
Cerebellar Granule Cell ◽  
In Ovo ◽  
Differentiation Markers ◽  
Fixed Tissue ◽  
Cerebellar Granule ◽  
Sequence Of Events ◽  
Granule Cell Precursors

Cerebellar granule cell precursors (GCPs) form a secondary germinative epithelium, the external germinal layer (EGL) where they proliferate extensively to produce the most numerous cell type in the brain. The morphological sequence of events that characterizes the differentiation of GCPs in the EGL is well established. However, morphologies of individual GCP and their differentiation status have never been correlated. Here, we examine the morphological features and transitions of GCPs in the chicken cerebellum by labelling a subset of GCPs with a stable genomic expression of a GFP transgene and following their development within the EGL in fixed tissue and using time-lapse imaging. We use immunohistochemistry to observe cellular morphologies of mitotic and differentiating GCPs to better understand their differentiation dynamics. Results reveal that mitotic activities of GCPs are more complex and dynamic than currently appreciated. While most GCPs divide in the outer and middle EGL, some are capable of division in the inner EGL. Some GCPs remain mitotically active during process extension and tangential migration and retract their processes prior to each cell division. The mitotically active precursors can also express differentiation markers such as TAG1 and NeuroD1. Further, we explore the result of misexpression of NeuroD1 on granule cell development. When misexpressed in GCPs, NeuroD1 leads to premature differentiation, defects in migration and reduced cerebellar size and foliation. Overall, we provide the first characterisation of individual morphologies of mitotically active cerebellar GCPs in ovo and reaffirm the role of NeuroD1 as a differentiation factor in the development of cerebellar granule cells.

scholarly journals Overlapping functions of the cell adhesion molecules Nr-CAM and L1 in cerebellar granule cell development

2001 ◽  
Vol 154 (6) ◽  
pp. 1259-1274 ◽  
Author(s):  
Takeshi Sakurai ◽  
Marc Lustig ◽  
Joanne Babiarz ◽  
Andrew J.W. Furley ◽  
Steven Tait ◽  
...  
Keyword(s):  
Cell Adhesion ◽  
Adhesion Molecules ◽  
Granule Cell ◽  
Cell Adhesion Molecules ◽  
Granule Cells ◽  
Cerebellar Granule Cells ◽  
Cell Development ◽  
Cerebellar Granule Cell ◽  
Granule Cell Layer ◽  
Cerebellar Granule

The structurally related cell adhesion molecules L1 and Nr-CAM have overlapping expression patterns in cerebellar granule cells. Here we analyzed their involvement in granule cell development using mutant mice. Nr-CAM–deficient cerebellar granule cells failed to extend neurites in vitro on contactin, a known ligand for Nr-CAM expressed in the cerebellum, confirming that these mice are functionally null for Nr-CAM. In vivo, Nr-CAM–null cerebella did not exhibit obvious histological defects, although a mild size reduction of several lobes was observed, most notably lobes IV and V in the vermis. Mice deficient for both L1 and Nr-CAM exhibited severe cerebellar folial defects and a reduction in the thickness of the inner granule cell layer. Additionally, anti-L1 antibodies specifically disrupted survival and maintenance of Nr-CAM–deficient granule cells in cerebellar cultures treated with antibodies. The combined results indicate that Nr-CAM and L1 play a role in cerebellar granule cell development, and suggest that closely related molecules in the L1 family have overlapping functions.

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.

BDNF stimulates migration of cerebellar granule cells

Development ◽  
2002 ◽  
Vol 129 (6) ◽  
pp. 1435-1442 ◽  
Author(s):  
Paul R. Borghesani ◽  
Jean Michel Peyrin ◽  
Robyn Klein ◽  
Joshua Rubin ◽  
Alexandre R. Carter ◽  
...  
Keyword(s):  
Granule Cell ◽  
Granule Cells ◽  
Cerebellar Granule Cells ◽  
Cell Layer ◽  
Time Lapse ◽  
Granule Cell Layer ◽  
Boyden Chamber ◽  
Cerebellar Granule ◽  
Proliferative Zone ◽  
On Line

During development of the nervous system, neural progenitors arise in proliferative zones, then exit the cell cycle and migrate away from these zones. Here we show that migration of cerebellar granule cells out of their proliferative zone, the external granule cell layer (EGL), is impaired in Bdnf–/– mice. The reason for impaired migration is that BDNF directly and acutely stimulates granule cell migration. Purified Bdnf–/– granule cells show defects in initiation of migration along glial fibers and in Boyden chamber assays. This phenotype can be rescued by exogenous BDNF. Using time-lapse video microscopy we find that BDNF is acutely motogenic as it stimulates migration of individual granule cells immediately after addition. The stimulation of migration reflects both a chemokinetic and chemotactic effect of BDNF. Collectively, these data demonstrate that BDNF is directly motogenic for granule cells and provides a directional cue promoting migration from the EGL to the internal granule cell layer (IGL). Movies available on-line

scholarly journals Cerebellar granule cells contain a membrane mitogen for cultured Schwann cells.

1989 ◽  
Vol 108 (2) ◽  
pp. 607-611 ◽  
Author(s):  
P W Mason ◽  
J W Bigbee ◽  
G H DeVries
Keyword(s):  
Cell Proliferation ◽  
Schwann Cell ◽  
Schwann Cells ◽  
Cell Cultures ◽  
Granule Cell ◽  
Granule Cells ◽  
Cerebellar Granule Cells ◽  
Proteoglycan Synthesis ◽  
Cerebellar Granule ◽  
Mitogenic Signal

Proliferation of Schwann cells is one of the first events that occurs after contact with a growing axon. To further define the distribution and properties of this axonal mitogen, we have (a) cocultured cerebellar granule cells, which lack glial ensheathment in vivo with Schwann cells; and (b) exposed Schwann cell cultures to isolated granule cell membranes. Schwann cells cocultured with granule cells had a 30-fold increase in the labeling index over Schwann cells cultured alone, suggesting that the mitogen is located on the granule cell surface. Inhibition of granule cell proteoglycan synthesis caused a decrease in the granule cells' ability to stimulate Schwann cell proliferation. Membranes isolated from cerebellar granule cells when added to Schwann cell cultures caused a 45-fold stimulation in [3H]thymidine incorporation. The granule cell mitogenic signal was heat and trypsin sensitive and did not require lysosomal processing by Schwann cells to elicit its proliferative effect. The ability of granule cells and their isolated membranes to stimulate Schwann cell proliferation suggests that the mitogenic signal for Schwann cells is a ubiquitous factor present on all axons regardless of their ultimate state of glial ensheathment.

scholarly journals Plasticity of cerebellar granule cell precursors.

2003 ◽  
Vol 79B (7) ◽  
pp. 223-226 ◽  
Author(s):  
Takayuki OKANO-UCHIDA ◽  
Toshiyuki HIMI ◽  
Yoshiaki KOMIYA ◽  
Yasuki ISHIZAKI
Keyword(s):  
Granule Cell ◽  
Cerebellar Granule Cell ◽  
Cerebellar Granule ◽  
Granule Cell Precursors
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