Presentation Title

Influence of Myelin-Associated Glycoprotein on axon subtype specific sheath targeting

Presenter Information

Nazmus Sakib KhanFollow

Abstract

During the development of the Central Nervous System, oligodendrocytes wrap axons with myelin, which is necessary for rapid, efficient nerve impulse propagation. For reasons unknown, oligodendrocytes direct myelin to certain subtypes of axons, leaving others incompletely myelinated, or even totally unmyelinated. Previous studies demonstrated mice harboring Mag mutations showed improper sheath targeting of myelin to axons indicating that MAG is a possible facilitator of axon-glia communication.

In the present study, we tested the hypothesis that loss of mag decreases the proportion of myelin directed towards specific axon subtypes. To test this, we perturbed Mag function in zebrafish embryos using knockdown and knockout (KO) mutant analysis and observed changes in myelin sheath distribution in reticulospinal projection and dopaminergic projection neurons. Our results indicated that loss of mag caused a significant decrease in the amount of myelin wrapping of reticulospinal projections, mainly due to fewer number of sheaths, and to a lesser extent, decreased average sheath length.

The results support the hypothesis that loss of Mag reduces the proportion of myelin directed towards specific axon subtypes by reducing the number of sheaths being made, and of the sheaths made, a reduced proportion of them was directed towards reticulospinal axons in comparison to the control group.

These findings advanced knowledge about adaptive myelination by showing that Mag influences sheath targeting amongst axon subtypes. Furthermore, Mag is the first protein discovered that affects sheath distribution across regions.

Currently, we are analyzing data for dopaminergic projection axon subtypes.

College

College of Science & Engineering

Department

Biology

Location

Winona, MN

Breakout Room

32

Start Date

4-14-2021 3:00 PM

End Date

4-14-2021 3:45 PM

Presentation Type

Video (Live-Zoom)

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Apr 14th, 3:00 PM Apr 14th, 3:45 PM

Influence of Myelin-Associated Glycoprotein on axon subtype specific sheath targeting

Winona, MN

During the development of the Central Nervous System, oligodendrocytes wrap axons with myelin, which is necessary for rapid, efficient nerve impulse propagation. For reasons unknown, oligodendrocytes direct myelin to certain subtypes of axons, leaving others incompletely myelinated, or even totally unmyelinated. Previous studies demonstrated mice harboring Mag mutations showed improper sheath targeting of myelin to axons indicating that MAG is a possible facilitator of axon-glia communication.

In the present study, we tested the hypothesis that loss of mag decreases the proportion of myelin directed towards specific axon subtypes. To test this, we perturbed Mag function in zebrafish embryos using knockdown and knockout (KO) mutant analysis and observed changes in myelin sheath distribution in reticulospinal projection and dopaminergic projection neurons. Our results indicated that loss of mag caused a significant decrease in the amount of myelin wrapping of reticulospinal projections, mainly due to fewer number of sheaths, and to a lesser extent, decreased average sheath length.

The results support the hypothesis that loss of Mag reduces the proportion of myelin directed towards specific axon subtypes by reducing the number of sheaths being made, and of the sheaths made, a reduced proportion of them was directed towards reticulospinal axons in comparison to the control group.

These findings advanced knowledge about adaptive myelination by showing that Mag influences sheath targeting amongst axon subtypes. Furthermore, Mag is the first protein discovered that affects sheath distribution across regions.

Currently, we are analyzing data for dopaminergic projection axon subtypes.