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Differentiation and death of premyelinating oligodendrocytes in developing rodent brain.

Trapp BD, Nishiyama A, Cheng D, Macklin W - J. Cell Biol. (1997)

Bottom Line: These premyelinating oligodendrocytes have one of two fates: they myelinate axons or degenerate.Between 7 and 21 d after birth, approximately 20% of premyelinating oligodendrocytes identified in the cerebral cortex were degenerating.Oligodendrocytes that ensheathed axons expressed and selectively targeted proteolipid protein to compact myelin and did not degenerate.

View Article: PubMed Central - PubMed

Affiliation: Department of Neurosciences, Research Institute, The Cleveland Clinic Foundation, Ohio 44195, USA.

ABSTRACT
Previous studies have indicated that newly formed oligodendrocytes are dynamic cells whose production, survival, and differentiation depend upon axonal influences. This study has characterized the appearance and fate of newly formed oligodendrocytes in developing rat brain. Oligodendrocytes appear in predictable locations and radially extend DM-20-positive processes that cover 80-microm domains in the cortex and 40-microm domains in the corpus callosum. These premyelinating oligodendrocytes have one of two fates: they myelinate axons or degenerate. Between 7 and 21 d after birth, approximately 20% of premyelinating oligodendrocytes identified in the cerebral cortex were degenerating. Oligodendrocytes that ensheathed axons expressed and selectively targeted proteolipid protein to compact myelin and did not degenerate. These observations support the hypothesis that axonal influences affect oligodendrocyte survival, differentiation, and expression of proteolipid protein gene products.

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Premyelinating oligodendrocytes differentiate into myelinating oligodendrocytes. DM-20/PLP–positive oligodendrocytes  before myelination (A), during early stages of axonal ensheathment (B, arrowheads), and during active myelination (C). Bar, 10 μm.
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Figure 4: Premyelinating oligodendrocytes differentiate into myelinating oligodendrocytes. DM-20/PLP–positive oligodendrocytes before myelination (A), during early stages of axonal ensheathment (B, arrowheads), and during active myelination (C). Bar, 10 μm.

Mentions: The distribution of DM-20/PLP immunoreactivity indicated that premyelinating oligodendrocytes differentiate into myelinating oligodendrocytes in predictable locations in the cerebral cortex. Fig. 4 depicts three stages in the progression from premyelinating to myelin-forming oligodendrocyte. The premyelinating oligodendrocyte in Fig. 4 A radially extends DM-20/PLP–positive processes that have no obvious extensions along axons. Initial stages of myelination can be identified by the extension of T-shaped processes from the premyelinating oligodendrocytes (Fig. 4 B, arrowheads). The top of the T's are oriented parallel to axonal bundles and represent initial stages of axonal ensheathment. Analysis of cells in more advanced stages of myelination (Fig. 4 C) indicated that only a small percentage of the premyelinating oligodendrocyte processes ensheath axons. Fragmented DM-20/PLP–positive processes were not detected near developing myelin internodes, suggesting that premyelinating oligodendrocyte processes that do not ensheath axons were resorbed.


Differentiation and death of premyelinating oligodendrocytes in developing rodent brain.

Trapp BD, Nishiyama A, Cheng D, Macklin W - J. Cell Biol. (1997)

Premyelinating oligodendrocytes differentiate into myelinating oligodendrocytes. DM-20/PLP–positive oligodendrocytes  before myelination (A), during early stages of axonal ensheathment (B, arrowheads), and during active myelination (C). Bar, 10 μm.
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Related In: Results  -  Collection

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Figure 4: Premyelinating oligodendrocytes differentiate into myelinating oligodendrocytes. DM-20/PLP–positive oligodendrocytes before myelination (A), during early stages of axonal ensheathment (B, arrowheads), and during active myelination (C). Bar, 10 μm.
Mentions: The distribution of DM-20/PLP immunoreactivity indicated that premyelinating oligodendrocytes differentiate into myelinating oligodendrocytes in predictable locations in the cerebral cortex. Fig. 4 depicts three stages in the progression from premyelinating to myelin-forming oligodendrocyte. The premyelinating oligodendrocyte in Fig. 4 A radially extends DM-20/PLP–positive processes that have no obvious extensions along axons. Initial stages of myelination can be identified by the extension of T-shaped processes from the premyelinating oligodendrocytes (Fig. 4 B, arrowheads). The top of the T's are oriented parallel to axonal bundles and represent initial stages of axonal ensheathment. Analysis of cells in more advanced stages of myelination (Fig. 4 C) indicated that only a small percentage of the premyelinating oligodendrocyte processes ensheath axons. Fragmented DM-20/PLP–positive processes were not detected near developing myelin internodes, suggesting that premyelinating oligodendrocyte processes that do not ensheath axons were resorbed.

Bottom Line: These premyelinating oligodendrocytes have one of two fates: they myelinate axons or degenerate.Between 7 and 21 d after birth, approximately 20% of premyelinating oligodendrocytes identified in the cerebral cortex were degenerating.Oligodendrocytes that ensheathed axons expressed and selectively targeted proteolipid protein to compact myelin and did not degenerate.

View Article: PubMed Central - PubMed

Affiliation: Department of Neurosciences, Research Institute, The Cleveland Clinic Foundation, Ohio 44195, USA.

ABSTRACT
Previous studies have indicated that newly formed oligodendrocytes are dynamic cells whose production, survival, and differentiation depend upon axonal influences. This study has characterized the appearance and fate of newly formed oligodendrocytes in developing rat brain. Oligodendrocytes appear in predictable locations and radially extend DM-20-positive processes that cover 80-microm domains in the cortex and 40-microm domains in the corpus callosum. These premyelinating oligodendrocytes have one of two fates: they myelinate axons or degenerate. Between 7 and 21 d after birth, approximately 20% of premyelinating oligodendrocytes identified in the cerebral cortex were degenerating. Oligodendrocytes that ensheathed axons expressed and selectively targeted proteolipid protein to compact myelin and did not degenerate. These observations support the hypothesis that axonal influences affect oligodendrocyte survival, differentiation, and expression of proteolipid protein gene products.

Show MeSH