Tuyển tập các báo cáo nghiên cứu về sinh học được đăng trên tạp chí sinh học Journal of Biology đề tài: Semaphorins deployed to repel cell migrants at spinal cord borders. | Journal of Biology BioMed Central Minireview Semaphorins deployed to repel cell migrants at spinal cord borders Sophie Chauvet and Geneviève Rougon Address CNRS UMR 6216 Université de la Méditerranée Developmental Biology Institute of Marseille Luminy Case 907 Parc Scientifique de Luminy 13288 Marseille cedex 09 France. Correspondence Geneviève Rougon. Email rougon@ Published 7 February 2008 Journal of Biology 2008 7 4 doi jbiol65 The electronic version of this article is the complete one and can be found online at http content 7 2 4 2008 BioMed Central Ltd Abstract In the spinal cord developing motor neurons extend their axons into the periphery while their cell bodies remain within the motor columns in the spinal cord. Two recent papers show that this partitioning involves forward and reverse semaphorin-plexin signaling between motor neurons and neural crest boundary cap cells. The vertebrate nervous system is subdivided into two main parts the central nervous system CNS and the peripheral nervous system PNS . Axons ensure connectivity between the CNS and the PNS but there is no mixing of cell bodies between the two. The interfaces between CNS and PNS compartments are the transitional zones in the spinal cord 1 . These are located at the motor exit point MEP where motor axons leave the cord in ventral roots and at the dorsal root entry zone DREZ where the afferents of primary sensory dorsal root ganglion neurons enter the spinal cord. In embryonic rodents and birds boundary cap cells BCCs reside at these segmental exit points 2 3 . BCCs are a small transient population of cells that arise from ventrally migrating neural crest cells. BCC progeny at the DREZ emigrate to populate distal structures where they differentiate into both glial and neuronal cells 4-6 . Elimination of BCCs at the MEP does not perturb motor axon outgrowth but results in motor neuron cell bodies migrating out of the spinal cord 7 . These observations led to
