2001 Fiscal Year Final Research Report Summary
Investigation on migration mechanisms of glial progenitors: observations of living cells labeled by dual fluorescent molecules
| Project/Area Number |
12680770
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Neuroscience in general
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| Research Institution | Niigata University |
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Principal Investigator |
KAKITA Akiyoshi Brain Research Institute, Niigata University, Associate Professor, 脳研究所, 助教授 (80281012)
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| Co-Investigator(Kenkyū-buntansha) |
YAMADA Mitsunori Brain Research Institute, Niigata University, Associate Professor, 脳研究所, 助教授 (30240039)
TAKAHASHI Hitoshi Brain Research Institute, Niigata University, Professor, 脳研究所, 教授 (90206839)
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| Project Period (FY) |
2000 – 2001
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| Keywords | subventricular zone / non-radial migration / tangential migration / radial fiber / glial progenitor / corpus callosum / retrovirus / fluorescent labeling |
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| Research Abstract |
The great majority of glial cells of the mammalian forebrain are generated in the perinatal period from progenitors in the subventricular zone (SVZ). We investigated the migration of progenitors from the neonatal (postnatal day 0, PO) rat forebrain SVZ by labeling them in vivo with a GFP-retrovirus, and monitoring their movements by time-lapse video microscopy in P3 slices. We identified a small number of progenitors that migrated tangentially within the corpus callosum (CC) and crossed the midline. These retained a relatively uniform morphology: the leading process was extended toward the contralateral side, but showed no process branching or turning away from the migratory direction. Net migration requires the elongation of the leading process and nuclear translocation, and the migrating cells in the CC showed both modes. We confirmed the presence of unmyelinated axon bundles within the P3 CC, but failed to detect any radially directed glial processes (vimentin- or GLAST-immunolabeled fibers) spanning through the CC. The destination of the callosal fibers was examined by applying DiI to the right cingulum; the labeled fibers ran throughout the CC and reached the left cingulate and motor areas. The distribution and final fates of the retrovirus-labeled cells were examined in P28 brains. A small proportion of the labeled cells, less than 1%, were found in the contralateral hemisphere, where, as oligodendrocytes and astrocytes, they colonized predominantly the cortex and the underlying white matter of the cingulate and secondary motor areas. The distribution pattern appears to coincide well with the projection direction of the callosal fibers. Thus, glial progenitors migrate across the CC, presumably in conjunction with unmyelinated axons, to colonize the contralateral hemisphere.
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