BEN/SC1/DM-GRASP expression during neuromuscular development: a cell adhesion molecule regulated by innervation

Area of Science:

• Neuroscience
• Developmental Biology
• Cell Biology

Background:

• BEN/SC1/DM-GRASP is an Ig superfamily cell adhesion molecule.
• It is transiently expressed during avian embryogenesis in motoneurons and other cell types.

Purpose of the Study:

• To investigate the expression pattern of BEN during neuromuscular development in chicks.
• To understand the role of innervation in regulating BEN expression at neuromuscular junctions.

Main Methods:

• Studied BEN expression in chick embryos during neuromuscular development.
• Utilized neural tube ablation to deprive embryos of innervation.
• Examined BEN expression in cultured muscle cells with and without neuronal co-culture.
• Analyzed BEN expression in postnatal muscles after nerve section and reinnervation.

Main Results:

• Both motoneurons and myoblasts express BEN during early development.
• BEN expression becomes restricted at neuromuscular contacts upon acetylcholine receptor clustering.
• Muscle cells intrinsically express BEN, even without innervation.
• Innervation by neurons downregulates BEN expression in muscle cells.
• Nerve section leads to widespread BEN expression in muscle fibers.
• Reinnervation results in BEN reexpression in motor axons and concentration at neuromuscular junctions.

Conclusions:

• BEN is intrinsically expressed by myogenic cells and its expression is regulated by innervation.
• BEN plays a role in both the formation of neuromuscular contacts during development and muscle reinnervation.
• The dynamic regulation of BEN expression is crucial for neuromuscular junction formation and repair.