Role of semaphorin III in the developing rodent trigeminal system

Emel Ulupinar*, Akash Datwani, Oded Behar, Hajime Fujisawa, Reha Erzurumlu

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

52 Scopus citations


Semaphorins are a large family of secreted and transmembrane glycoproteins. Sema III, a member of the Class III semaphorins is a potent chemorepulsive signal for subsets of sensory axons and steers them away from tissue regions with high levels of expression. Previous studies in mutant mice lacking sema III gene showed various neural and nonneural abnormalities. In this study, we focused on the developing trigeminal pathway of sema III knockout mice. We show that the peripheral and central trigeminal projections are impaired during initial pathway formation when they develop into distinct nerves or tracts. These axons defasciculate and compromise the normal bundling of nerves and restricted alignment of the central tract. In contrast to trigeminal projections, thalamocortical projections to the barrel cortex appear normal. Furthermore, sema III receptor, neuropilin, is expressed during a short period of development when the tract is laid down, but not in the developing thalamocortical pathway. Peripherally, trigeminal axons express neuropilin for longer duration than their central counterparts. In spite of projection errors, whisker follicle innervation appears normal and whisker-related patterns form in the trigeminal nuclei and upstream thalamic and cortical centers. Our observations suggest that sema III plays a limited role during restriction of developing trigeminal axons to proper pathways and tracts. Other molecular and cellular mechanisms must act in concert with semaphorins in ensuring target recognition, topographic order of projections, and patterning of neural connections.

Original languageAmerican English
Pages (from-to)281-292
Number of pages12
JournalMolecular and Cellular Neurosciences
Issue number4
StatePublished - Apr 1999
Externally publishedYes

Bibliographical note

Funding Information:
We are grateful to Dr. L. Reichardt for providing the TrkA antiserum. We also thank Mr. T. Ulupinar for his assistance with the figures. E. Ulupinar is supported by a predoctoral fellowship from the Higher Education Commission of Turkey and Osmangazi University. Research supported by NIH (NS32195 to R.E.).


Dive into the research topics of 'Role of semaphorin III in the developing rodent trigeminal system'. Together they form a unique fingerprint.

Cite this