論文 - 戸田　正博

Development of oligodendrocyte and myelination in the central nervous system.

Asou H., Murakami K., Toda M., Uyemura K.

Keio Journal of Medicine 44 （ 2 ） 47 - 52 1995年06月

ISSN  0022-9717

　概要を見る

<p>We demonstrated the cell lineage of oligodendrocytes from the glial precursor cells to mature oligodendrocytes forming myelin sheath around the axon. There are several different stages of oligodendrocyte development in vito. So far there are no precise data about their morphological changes during oligodendrocyte development, but by the analysis using SEM and immunostaining, the characteristic morphological changes with serial expression of cell markers were observed in each developmental steps of oligodendrocyte. We have also clearly demonstrated how oligodendrocytes wrap around the axon by using video time-lapse movies. These results will be useful for understanding the exact cellular mechanism of myelination in the CNS.</p>

Cell growth suppression of astrocytoma C6 cells by glial fibrillary acidic protein cDNA transfection

Toda Masahiro, Miura Masayuki, Asou Hiroaki, Toya Shigeo, Uyemura Keiichi

Journal of Neurochemistry 63 （ 5 ） 1975 - 1978 1994年11月

ISSN  0022-3042

　概要を見る

<p>The cellular functions of the intermediate filament family including glial fibrillary acidic protein (GFAP) are not well known yet beyond their roles as structural elements of cells. Expression of GFAP, which is specific in astrocytes and regulated developmentally, suggests its involvement in cell growth and differentiation of astrocytes. We transfected murine GFAP cDNA into a rat astrocytoma C6 cell line to assess the specific effect of GFAP on cells. Two stable GFAP-transfected cell lines, GFC6-5 and GFC6-6, exhibited a series of morphological and growth characteristics that distinguish them from their counterparts, i.e., NeoC6 cells transfected only with the neomycin- resistant gene, and native C6 cells. Both GFC6-5 and GFC6-6 cells showed elongated cell shapes with extended processes rich in GFAP, markedly suppressed cell growth, and decreased bromodeoxyuridine uptake. Western blot analysis revealed a remarkable increase of GFAP expression in GFC6-5 and GFC6-6 compared with that in NeoC6 and C6, in contrast to similar vimentin expression in all cell lines. The results indicate that the expression of GFAP has dramatic effects on cell morphology and cell growth suppression in C6 cells, suggesting that GFAP may function as a tumor suppressor in astrocytoma.</p>

GFAP transfected cells produce laminin, leading to neurite outgrowth promotion

Toda M., Asou H., Miura M., Toya S., Uyemura K.

NeuroReport 5 （ 15 ） 1969 - 1972 1994年

ISSN  0959-4965

　概要を見る

<p>Accumulating evidence indicates the importance of astrocytes in neuronal development and regeneration. While glial fibrillary acidic protein (GFAP) is believed to mediate the morphology of developing astrocytes, its precise function remains unknown. To analyse the function of GFAP in astrocytes, we established GFAP-expressing cell lines by transfection of mouse GFAP cDNA into mouse fibroblast L cells. Stable transfectants expressed GFAP uniformly in the cytoplasm with no phenotypic changes and exhibited extended processes rich in GFAP. GFAP-expressing cells significantly promoted the neurite outgrowth of rat cerebral cortex neurones in the co-culture system. Analysis of the products of GFAP-expressing cells revealed an increase in production of laminin, but not fibronectin. These results suggest that L cells expressing GFAP increase laminin production, leading to promotion of neurite outgrowth.</p>

Molecular-Cloning of cDNA Encoding Human Drebrin E and Chromosomal Mapping of Its Gene

Toda M., Shirao T., Minoshima S., Shimizu N., Toya S., Uyemura K.

Biochemical and Biophysical Research Communications 196 （ 1 ） 468 - 472 1993年10月

ISSN  0006-291X

　概要を見る

<p>Drebrins are novel actin-binding proteins in the brain which are developmentally regulated. Three isoforms: two embryonic types (El and E2) and an adult type (A) are generated by alternative RNA splicing from a single drebrin gene in the chicken brain. A full length cDNA clone of human drebrin E has been isolated from a cDNA library of human fetus brain. The clone is 2596 base pairs in length and contains an open reading frame of 1947 nucleotides encoding a protein of 649 amino acids. The deduced amino acid sequence, except for the internal 138-nucleotide sequence (ins2), exhibits 88% homology with rat drebrin A. Spot blot hybridization using flow-sorted human chromosomes provides evidence that the gene encoding human drebrin protein locates on human chromosome 5. © 1993 Academic Press. All rights reserved.</p>

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