The Role of Nogo-A During Development of the Chick Central Nervous System

<p>Nogo-A is a potent inhibitor of axon regeneration that is expressed by myelin forming oligodendrocytes of the adult central nervous system (CNS). However, neuronal expression of Nogo-A during development suggests an additional role. Little is known about the putative functions of Nogo-A during embryonic development. To examine its potential role we isolated and analyzed the Nogo-A sequence in the chick, we localized its mRNA expression pattern and cell-specific distribution during key phases of cortical development, and studied regulation of its expression during phases that showed promise of function based on expression patterns.</p> <p>Our results revealed five previously undescribed Nogo-A specific regions from multiple alignment of divergent species. The <em>Nogo</em> gene is differentially expressed during development and we identified a secondary <em>Nogo-A</em> splice variant. <em>In situ</em> hybridization found <em>Nogo-A</em> induction to be coincident with formation of the neural plate, the first visible structure of the CNS. Expression remained diffuse within the neuroepithelia and during later stages of cortical development (proliferation and migration) but showed an increased distribution in large projection neurons during organization of the neuronal network. In addition, we found <em>Nogo-A</em> to be regulated by FGF application, but not by synaptic activity. We identified evolutionarily conserved regulatory sequences surrounding the Nogo gene locus. While they did not appear to play a role in regulating gene expression during early neural development, whether they play a role in later CNS development has yet to be determined. Collectively, these data suggest Nogo-A plays a role in the determination of neural identity and/or differentiation and also appears to play a later role in the networking of large projection neurons during neurite formation and synaptogenesis.</p>

Name thesis:degree_name

Doctor of Philosophy (PhD)

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Anatomy

Year

2007

Author dc:creator

• Caltharp, Shelly A.

Contributors dc:contributor

• Kerby Oberg
• Denise Bellinger
• William Fletcher
• Wolff Kirsch
• Nathan Wall

• Anatomy
• Genetic Structures
• Nervous System
• Neuroscience and Neurobiology
• Central Nervous System -- growth and development; Embryonic Development; Chick Embryo -- growth and development; Myelin Proteins; Axons.

Statement dc:rights

• This title appears here courtesy of the author, who has granted Loma Linda University a limited, non-exclusive right to make this publication available to the public. The author retains all other copyrights.

Language dc:language

English

Repository record dc:identifier

https://scholarsrepository.llu.edu/etd/1754

OAI identifier oai:identifier

oai:scholarsrepository.llu.edu:etd-2381