Turtle interacts with borderless in regulating glial extension and axon ensheathment.

Area of Science:

• Neuroscience
• Developmental Biology
• Cell Biology

Background:

• Axon ensheathment by glial cells is essential for nervous system development.
• Proper axon-glia recognition guides glial process extension and ensheathment.
• The transmembrane protein Borderless (Bdl) in glia is known to be involved in this process.

Purpose of the Study:

• To elucidate the molecular mechanism by which Borderless (Bdl) mediates axon-glia recognition.
• To identify interacting partners of Bdl involved in glial extension and axon ensheathment.

Main Methods:

• Interaction studies in cultured cells.
• Genetic analysis in Drosophila.
• Analysis of protein expression patterns.

Main Results:

• Identified Turtle (Tutl), an Ig transmembrane protein in photoreceptor axons, as an interaction partner of Bdl.
• Loss of Tutl in axons phenocopies the effects of Bdl loss in glia, disrupting glial extension and axon ensheathment.
• Tutl and Bdl interact genetically and in trans, suggesting a direct interaction.

Conclusions:

• Turtle (Tutl) interacts with Borderless (Bdl) to mediate axon-glia recognition.
• This interaction is critical for wrapping glia extension and photoreceptor axon ensheathment in Drosophila.
• The Tutl-Bdl complex represents a key molecular mechanism for developmental axon-glia communication.