The Enigmatic Reissner’s Fiber and the Origin of Chordates

Front. Neuroanat., 2021 · DOI: 10.3389/fnana.2021.703835 · Published: June 23, 2021

Simple Explanation

Reissner's fiber (RF) is a thread-like structure found in the spinal cord of chordates, a group of animals that includes vertebrates like us. Although it was discovered a long time ago, scientists are still unsure about its exact purpose. Recent research suggests that RF might be important for the proper development of the spine and body axis in chordates. It may also play a role in how chordates sense their body position and move through the water. Understanding RF could provide insights into conditions like hydrocephalus and scoliosis and even help us find new ways to treat spinal cord injuries.

Study Duration

Not specified

Participants

Not specified

Evidence Level

Review

Key Findings

1
RF is a highly conserved structure in chordates, suggesting it plays a fundamental role.
2
RF may contribute to the formation and maintenance of the neural tube, a key feature of chordates.
3
RF appears to be involved in the development of a straight body axis and swimming behavior in chordates.

Research Summary

This article reviews the evidence for a role of Reissner's fiber (RF) in the origin of fundamental innovations of the chordate body plan, especially the elongation of the neural tube and maintenance of the body axis. RF is an insoluble proteinaceous ﬁlament that ﬂoats in the CSF inside the chordate NCa. It is secreted by specialized ependymal cells in the mesencephalic-diencephalic (M-D) junction and extends toward the caudal end of the neural tube. The authors hypothesize that the assembly of RF as a growing ﬁlament in the rudimentary NCa of chordate ancestors contributed to the extension of the neural tube into the tail region in concomitance with the diﬀerentiation of the notochord.

Practical Implications

Understanding Chordate Evolution

RF provides insights into the evolutionary origins of key chordate features like the neural tube and body axis.

Treating Spinal Disorders

Understanding RF's role in neural development may contribute to the treatment of spinal cord disorders, including hydrocephalus and scoliosis.

Spinal Cord Regeneration

Further research into RF's role in lengthening the neural canal and tail regeneration could lead to therapeutic interventions for spinal cord injuries.

Study Limitations

1
Lack of clarity about RF's primary, fundamental function or adaptive significance.
2
More evidence needed to support the role of RF material in the early invagination of the nerve cord.
3
Further research is required to determine whether RF and CSF-cn participate in the ventral bending of the embryonic tail.

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