Limits...
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.

Show MeSH
Comparison of the distribution of DM-20/PLP (red) and PLP (green) in confocal images of oligodendrocytes. Areas of colocalization appear yellow. During early stages of axonal ensheathment, DM-20/PLP immunoreactivity is evenly distributed on oligodendrocyte processes (A, red) and developing myelin internodes (A, red and yellow), while PLP-specific immunoreactivity is restricted to  perinuclear cytoplasm and developing myelin internodes (A, yellow). In more mature oligodendrocytes, DM-20/PLP is detected in oligodendrocyte processes and myelin, while PLP is restricted to perinuclear cytoplasm and myelin (B, yellow). Asterisks and arrowheads  denote nucleus of cell and myelin internodes. Bars, 10 μm.
© Copyright Policy
Related In: Results  -  Collection


getmorefigures.php?uid=PMC2139778&req=5

Figure 5: Comparison of the distribution of DM-20/PLP (red) and PLP (green) in confocal images of oligodendrocytes. Areas of colocalization appear yellow. During early stages of axonal ensheathment, DM-20/PLP immunoreactivity is evenly distributed on oligodendrocyte processes (A, red) and developing myelin internodes (A, red and yellow), while PLP-specific immunoreactivity is restricted to perinuclear cytoplasm and developing myelin internodes (A, yellow). In more mature oligodendrocytes, DM-20/PLP is detected in oligodendrocyte processes and myelin, while PLP is restricted to perinuclear cytoplasm and myelin (B, yellow). Asterisks and arrowheads denote nucleus of cell and myelin internodes. Bars, 10 μm.

Mentions: The proteolipid protein gene produces two alternatively spliced proteins (DM-20 and PLP) that differ by 35 additional amino acids (exon 3b) in PLP. Previous studies have indicated that DM-20 is expressed before PLP during brain development (Macklin, 1992; Timsit et al., 1995). To determine if DM-20 and PLP could be detected at different stages of oligodendrocyte differentiation, sections were double-labeled with one antibody specific for DM20/PLP and another specific for PLP. Premyelinating and myelinating oligodendrocytes were identified and examined by confocal microscopy. The PLP-specific antibody did not stain premyelinating oligodendrocytes. During early stages of myelin formation (cells extending multiple DM-20/PLP–positive processes and short DM-20/PLP– positive developing myelin internodes), PLP was detected in oligodendrocyte perinuclear cytoplasm and in some of the developing internodes (Fig. 5 A). At later stages of myelination (Fig. 5 B), all developing myelin internodes were both DM-20/PLP and PLP positive. These observations indicate that PLP is expressed at very low levels in premyelinating oligodendrocytes and during early stages of axonal ensheathment and that PLP is targeted exclusively to myelin internodes. In contrast, DM-20 was detected on all surface membranes of premyelinating and myelinating oligodendrocytes. These observations raise the possibility that axonal influences regulate differential expression of PLP gene products as premyelinating oligodendrocytes differentiate into myelinating oligodendrocytes.


Differentiation and death of premyelinating oligodendrocytes in developing rodent brain.

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

Comparison of the distribution of DM-20/PLP (red) and PLP (green) in confocal images of oligodendrocytes. Areas of colocalization appear yellow. During early stages of axonal ensheathment, DM-20/PLP immunoreactivity is evenly distributed on oligodendrocyte processes (A, red) and developing myelin internodes (A, red and yellow), while PLP-specific immunoreactivity is restricted to  perinuclear cytoplasm and developing myelin internodes (A, yellow). In more mature oligodendrocytes, DM-20/PLP is detected in oligodendrocyte processes and myelin, while PLP is restricted to perinuclear cytoplasm and myelin (B, yellow). Asterisks and arrowheads  denote nucleus of cell and myelin internodes. Bars, 10 μm.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2139778&req=5

Figure 5: Comparison of the distribution of DM-20/PLP (red) and PLP (green) in confocal images of oligodendrocytes. Areas of colocalization appear yellow. During early stages of axonal ensheathment, DM-20/PLP immunoreactivity is evenly distributed on oligodendrocyte processes (A, red) and developing myelin internodes (A, red and yellow), while PLP-specific immunoreactivity is restricted to perinuclear cytoplasm and developing myelin internodes (A, yellow). In more mature oligodendrocytes, DM-20/PLP is detected in oligodendrocyte processes and myelin, while PLP is restricted to perinuclear cytoplasm and myelin (B, yellow). Asterisks and arrowheads denote nucleus of cell and myelin internodes. Bars, 10 μm.
Mentions: The proteolipid protein gene produces two alternatively spliced proteins (DM-20 and PLP) that differ by 35 additional amino acids (exon 3b) in PLP. Previous studies have indicated that DM-20 is expressed before PLP during brain development (Macklin, 1992; Timsit et al., 1995). To determine if DM-20 and PLP could be detected at different stages of oligodendrocyte differentiation, sections were double-labeled with one antibody specific for DM20/PLP and another specific for PLP. Premyelinating and myelinating oligodendrocytes were identified and examined by confocal microscopy. The PLP-specific antibody did not stain premyelinating oligodendrocytes. During early stages of myelin formation (cells extending multiple DM-20/PLP–positive processes and short DM-20/PLP– positive developing myelin internodes), PLP was detected in oligodendrocyte perinuclear cytoplasm and in some of the developing internodes (Fig. 5 A). At later stages of myelination (Fig. 5 B), all developing myelin internodes were both DM-20/PLP and PLP positive. These observations indicate that PLP is expressed at very low levels in premyelinating oligodendrocytes and during early stages of axonal ensheathment and that PLP is targeted exclusively to myelin internodes. In contrast, DM-20 was detected on all surface membranes of premyelinating and myelinating oligodendrocytes. These observations raise the possibility that axonal influences regulate differential expression of PLP gene products as premyelinating oligodendrocytes differentiate into myelinating oligodendrocytes.

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