Expression patterns of <it>semaphorin7A </it>and <it>plexinC1 </it>during rat neural development suggest roles in axon guidance and neuronal migration

• Main Authors: Hellemons Anita JCGM, Kolk Sharon M, Pasterkamp R Jeroen, Kolodkin Alex L
• Format: Article
• Language: English
• Published: BMC 2007-08-01
• Series: BMC Developmental Biology
• Online Access: http://www.biomedcentral.com/1471-213X/7/98

<p>Abstract</p> <p>Background</p> <p>Although originally identified as embryonic axon guidance cues, semaphorins are now known to regulate multiple, distinct, processes crucial for neuronal network formation including axon growth and branching, dendritic morphology, and neuronal migration. Semaphorin7A (Sema7A), the only glycosylphosphatidylinositol-anchored semaphorin, promotes axon growth in vitro and is required for the proper growth of the mouse lateral olfactory tract in vivo. Sema7A has been postulated to signal through two unrelated receptors, an RGD-dependent α1β1-integrin and a member of the plexin family, plexinC1. β1-integrins underlie Sema7A-mediated axon growth and Sema7A function in the immune system. Sema7A-plexinC1 interactions have also been implicated in immune system function, but the neuronal role of this ligand-receptor pair remains to be explored. To gain further insight into the function(s) of Sema7A and plexinC1 during neural development, we present here a detailed analysis of <it>Sema7A </it>and <it>plexinC1 </it>expression in the developing rat nervous system.</p> <p>Results</p> <p>In situ hybridization revealed select expression of <it>Sema7A </it>and <it>plexinC1 </it>in multiple neuronal systems including: the olfactory system, the hypothalamo-hypophysial system, the hippocampus, the meso-diencephalic dopamine system, and the spinal cord. Within these systems, <it>Sema7A </it>and <it>plexinC1 </it>are often expressed in specific neuronal subsets. In general, <it>Sema7A </it>transcript levels increase significantly towards adulthood, whereas <it>plexinC1 </it>expression decreases as development proceeds.</p> <p><it>PlexinC1</it>, but not <it>Sema7A</it>, is strongly expressed by distinct populations of migrating neurons. In addition to neuronal expression, <it>Sema7A </it>and <it>plexinC1 </it>transcripts were detected in oligodendrocytes and ependymal cells, respectively.</p> <p>Conclusion</p> <p><it>Sema7A </it>and <it>plexinC1 </it>expression patterns are consistent with these proteins serving both cooperative and separate functions during neural development. The prominent expression of <it>plexinC1 </it>in several distinct populations of migrating neurons suggests a novel role for this plexin family member in neuronal migration.</p>