[HTML][HTML] DCC mediated axon guidance of spinal interneurons is essential for normal locomotor central pattern generator function

NR Bernhardt, F Memic, H Gezelius, AL Thiebes… - Developmental …, 2012 - Elsevier
NR Bernhardt, F Memic, H Gezelius, AL Thiebes, A Vallstedt, K Kullander
Developmental biology, 2012Elsevier
Coordinated limb rhythmic movements take place through organized signaling in local
spinal cord neuronal networks. The establishment of these circuitries during development is
dependent on the correct guidance of axons to their targets. It has previously been shown
that the well-known axon guidance molecule netrin-1 is required for configuring the circuitry
that provides left–right alternating coordination in fictive locomotion. The attraction of
commissural axons to the midline in response to netrin-1 has been shown to involve the …
Coordinated limb rhythmic movements take place through organized signaling in local spinal cord neuronal networks. The establishment of these circuitries during development is dependent on the correct guidance of axons to their targets. It has previously been shown that the well-known axon guidance molecule netrin-1 is required for configuring the circuitry that provides left–right alternating coordination in fictive locomotion. The attraction of commissural axons to the midline in response to netrin-1 has been shown to involve the netrin-1 receptor DCC (deleted in Colorectal Cancer). However, the role of DCC for the establishment of CPG coordination has not yet been resolved. We show that mice carrying a null mutation of DCC displayed an uncoordinated left–right activity during fictive locomotion accompanied by a loss of interneuronal subpopulations originating from commissural progenitors. Thus, DCC plays a crucial role in the formation of spinal neuronal circuitry coordinating left–right activities. Together with the previously published results from netrin-1 deficient mice, the data presented in this study suggest a role for the most ventral originating V3 interneurons in synchronous activities over the midline. Further, it provides evidence that axon crossing in the spinal cord is more intricately controlled than in previously suggested models of DCC-netrin-1 interaction.
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