Showing papers on "Radial glial cell published in 1992"
TL;DR: To reconcile the observations that many radialglia are present early, that radial glia are among the last offspring of a multipotential stem cell, and that most clones contain only a single radial glial cell, it is suggested that the stem cell is, or becomes, a radial glio cell.
Abstract: In many parts of the central nervous system, the elongated processes of radial glial cells are believed to guide immature neurons from the ventricular zone to their sites of differentiation. To study the clonal relationships of radial glia to other neural cell types, we used a recombinant retrovirus to label precursor cells in the chick optic tectum with a heritable marker, the E. coli lacZ gene. The progeny of the infected cells were detected at later stages of development with a histochemical stain for the lacZ gene product. Radial glia were identified in a substantial fraction of clones, and these were studied further. Our main results are the following. (a) Clones containing radial glia frequently contained neurons and/or astrocytes, but usually not other radial glia. Thus, radial glia derive from a multipotential progenitor rather than from a committed radial glial precursor. (b) Production of radial glia continues until at least embryonic day (E) 8, after the peak of neuronal birth is over (approximately E5) and after radial migration of immature neurons has begun (E6-7). Radial glial and neuronal lineages do not appear to diverge during this interval, and radial glia are among the last cells that their progenitors produce. (c) As they migrate, many cells are closely apposed to the apical process of their sibling radial glia. Thus, radial glia may frequently guide the migration of their clonal relatives. (d) The population of labelled radial glia declines between E15 and E19-20 (just before hatching), concurrent with a sharp increase in the number of labelled astrocytes. This result suggests that some tectal radial glia transform into astrocytes, as occurs in mammalian cerebral cortex, although others persist after hatching. To reconcile the observations that many radial glia are present early, that radial glia are among the last offspring of a multipotential stem cell, and that most clones contain only a single radial glial cell, we suggest that the stem cell is, or becomes, a radial glial cell.
184 citations
TL;DR: These findings suggest that most astrocytes destined for the supragranular cortical layers are produced in the germinative zone after the migration of the infragranular neurons and themselves migrate afterwards to the upper cortex between E16 and the first postnatal days.
Abstract: The origin of astrocytes of the mouse neocortex during the fetal and early postnatal periods as determined by immunocytological, autoradiographic, electron microscopic and antimitotic methods is described. Most astrocytes destined for the white matter and the infragranular cortical layers are derived from the transformation of radial glial cells between P0 and P10 with an inside-out pattern. This cell metamorphosis is not directly preceded by mitosis and involves the activation of the radial glial lysosomal apparatus. In opposition to recent hypotheses, our findings suggest that most astrocytes destined for the supragranular cortical layers are produced in the germinative zone after the migration of the infragranular neurons and themselves migrate afterwards to the upper cortex between E16 and the first postnatal days. These astrocytes do not display an intermediate stage of the radial glial cell and do not participate in the pattern of appearance of the deeper astrocytes. This second step of astrocytogenesis is a condition for normal cytoarchitectonic development and the maintenance of the supragranular layers, since the deprivation of the astrocytic equipment of the supragranular layers by an antimitotic drug drastically reduces the number of supragranular neurons.
134 citations
TL;DR: The gustatory centers and the tegment of the posterior rhombencephalon of the Iberian barb have been studied using anti-glial fibrillary acidic protein (anti-GFAP) and anti-vimentin immunohistochemical techniques and two immunopositive cell types were found: ependymocytes and radial astrocytes.
32 citations
01 Jan 1992
TL;DR: As adult salamanders appear to be capable not only of optic nerve regeneration but also of central nervous system regeneration, they are an exciting object for the investigation of regenerative processes.
Abstract: Central nervous system regeneration does not happen in the injured mammalian brain In contrast, most anamniotic vertebrates possess a regenerative capacity in their optic nerves as adults However, regeneration in other central nervous system tracts is fairly reduced Salamanders are unique in partially regenerating long supraspinal tracts after transection (Davis et al, 1989) As adult salamanders appear to be capable not only of optic nerve regeneration but also of central nervous system regeneration, they are an exciting object for the investigation of regenerative processes As glial cells are especially involved in the regeneration process, their identification, distribution and immunohistochemical properties in normal and lesioned animals is of great importance