From classical to current: Analyzing peripheral nervous system and spinal cord lineage and fate

Abstract

During vertebrate development, the central (CNS) and peripheral nervous systems (PNS) arise from the neural plate. Cells at the margin of the neural plate give rise to neural crest cells, which migrate extensively throughout the embryo, contributing to the majority of neurons and all of the glia of the PNS. The rest of the neural plate invaginates to form the neural tube, which expands to form the brain and spinal cord. The emergence of molecular cloning techniques and identification of fluorophores like Green Fluorescent Protein (GFP), together with transgenic and electroporation technologies, have made it possible to easily visualize the cellular and molecular events in play during nervous system formation. These lineage-tracing techniques have precisely demonstrated the migratory pathways followed by neural crest cells and increased knowledge about their differentiation into PNS derivatives. Similarly, in the spinal cord, lineage-tracing techniques have led to a greater understanding of the regional organization of multiple classes of neural progenitor and post-mitotic neurons along the different axes of the spinal cord and how these distinct classes of neurons assemble into the specific neural circuits required to realize their various functions. Here, we review how both classical and modern lineage and marker analyses have expanded our knowledge of early peripheral nervous system and spinal cord development.

Netrin1 Produced by Neural Progenitors, Not Floor Plate Cells, Is Required for Axon Guidance in the Spinal Cord

“…However, netrin1 transcript is also expressed by many progenitors in the VZ in the mouse spinal cord (Serafini et al, 1996), a region ubiquitously avoided by spinal axons (Figures S1A, S1B) (Butler and Bronner, 2015). To resolve the role of FP- versus VZ-derived netrin1, we have used multiple genetic approaches to determine the spatial requirement for netrin1 in the developing spinal cord.…”

Netrin1 establishes multiple boundaries for axon growth in the developing spinal cord

“…The spinal cord is organized into layers from its earliest genesis: Sox2 + neuroepithelial progenitors within the VZ give rise to postmitotic neurons that migrate laterally to form the mantle layer and extend axons in the lateral marginal zone (Butler and Bronner, 2015). Spinal axons can be broadly categorized by their protein complement: neurofilament (NF) is generally present in spinal axons, with Robo3 additionally being present in the commissural axons projecting towards FP at the ventral midline (Sabatier et al, 2004).…”

Nonviral Fluorescent Retrograde Tracers

“…The nervous system consisting of the central nervous system (CNS) and the peripheral nervous system (PNS) is a complex network of nerves and specialized cells, known as neurons that regulate actions, such as cellular basis, behavior, cognition, emotion, and consciousness . To date, many studies have indicated that various diseases are caused by abnormal neuronal wiring.…”