Showing papers on "Radial glial cell published in 2000"

Isolation of radial glial cells by fluorescent-activated cell sorting reveals a neuronal lineage.

Abstract: The developing central nervous system of vertebrates contains an abundant cell type designated radial glial cells. These cells are known as guiding cables for migrating neurons, while their role as precursor cells is less clear. Since radial glial cells express a variety of astroglial characteristics and differentiate as astrocytes after completing their guidance function, they have been considered as part of the glial lineage. Using fluorescence-activated cell sorting, we show here that radial glial cells also are neuronal precursors and only later, after neurogenesis, do they shift towards an exclusive generation of astrocytes. These results thus demonstrate a novel function for radial glial cells, namely their ability to generate two major cell types found in the nervous system, neurons and astrocytes.

Glial-defined rhombomere boundaries in developing Xenopus hindbrain.

Abstract: The vertebrate central nervous system is characterized by regional specialization, which arises during early development and contributes to patterning the emerging central nervous system (CNS). In the hindbrain, rhombomeres demarcate nonoverlapping regions of the CNS that give rise to distinct neural structures. The cellular structures that define boundaries between adjacent rhombomeres are as yet unclear. However, in certain species the boundary regions between discrete CNS regions appear to be defined by specialized glial cells. Here, we show that in developing Xenopus, DMγ, a membrane protein of the proteolipid protein family, is expressed in a subset of radial glia. During development, DMγ transcripts are first expressed in presumptive glial cells throughout the hindbrain, but later become confined to the ventricular zone at rhombomere centers, whereas the protein is exclusively expressed in radial glial cell processes that occupy the rhombomere boundary regions. Likewise, early in development vimentin and glial fibrillary acidic protein are extensively coexpressed in hindbrain radial glia but subsequently define distinct rhombomere domains: vimentin remains localized in radial glia at the rhombomere boundary regions, whereas expression of glial fibrillary acidic protein becomes restricted to the centers. Moreover, radial glial processes at the boundary region are distinguishable from those at the center region; the processes of the boundary region radial glia extend upward in a fan-shaped arrangement and are encircled by the processes from the center glia. These data suggest that an early event in determining rhombomere topology is the specification of both morphologically and biochemically distinct subsets of radial glia. J. Comp. Neurol. 424:47–57, 2000. © 2000 Wiley-Liss, Inc.

Wild-type and mutant forms of v-src differentially alter neuronal migration and differentiation in vivo.

Abstract: The effects of three different forms of v-src on brain cell development were determined in vivo. Recombinant retroviral vectors encoding the marker lacZ (control) and either wild-type v-src or SH2 or SH3 domain-deleted forms of v-src (deltaSH2 or deltaSH3, respectively) were used to infect neuronal progenitor cells in the embryonic chicken midbrain (optic tectum; OT). Embryos were injected in the OT with retroviral concentrates on embryonic day (E) 3 and sacrificed at E6, E9, and later in development. Patterns of cell proliferation, migration, and differentiation of lacZ-marked clonal cell progeny were then analyzed. Relative to lacZ-only controls, cell clone size at E6 was significantly increased for v-src-, unchanged for deltaSH2-, and smaller for deltaSH3-injected embryos. At E9, deltaSH2 cell clones were significantly larger than controls, suggesting increased survival from normal programmed cell death. Radial neuronal migration was impaired for v-src and deltaSH3 clones, whereas tangential neuronal migration was enhanced along fiber tracts in v-src and deltaSH2 clones. Moreover, radial glial cell development and differentiation was hindered in v-src and deltaSH3 clones. These experiments demonstrate that ectopic v-src signaling alters proliferation, migration, survival, and differentiation of developing brain cells and suggest that src signaling pathways are involved in these developmental processes. Furthermore, certain effects of v-src on brain cells require specific src homology domains.