Crim1 and Kelch-like 14 exert complementary dual-directional developmental control over segmentally specific...

Area of Science:

• Neuroscience
• Developmental Biology
• Molecular Biology

Background:

• The cerebral cortex controls skilled movement by connecting to brainstem and spinal motor circuits.
• Accurate targeting of spinal segments by corticospinal neurons (CSN) is essential but not well understood.
• Previous work identified molecular distinctions in CSN subpopulations, suggesting candidate regulators for axon targeting.

Purpose of the Study:

• To functionally investigate the roles of candidate molecules Crim1 and Klhl14 in CSN axon targeting.
• To determine how these molecules influence the projection patterns of CSN to specific spinal levels.

Main Methods:

• Functional investigation of Crim1 and Klhl14 in CSN subpopulations.
• Analysis of CSN axon extension and targeting within the white matter.
• Assessment of molecular regulation of differential white matter projection targeting.

Main Results:

• Crim1 and Klhl14 are expressed by distinct CSN subpopulations.
• Crim1 promotes thoracolumbar axon extension.
• Klhl14 restricts axon extension to bulbar-cervical segments.

Conclusions:

• Crim1 and Klhl14 are critical molecular regulators of CSN axon targeting to specific spinal segments.
• These molecules act prior to axon collateralization, guiding white matter projections.
• This study reveals early, complementary molecular controls over CSN diversity for distinct motor circuitry.