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Laumonnerie, Christophe
Publications (2 of 2) Show all publications
Open this publication in new window or tab >>Commissural axonal corridors instruct neuronal migration in the mouse spinal cord
2015 (English)In: Nature Communications, ISSN 2041-1723, E-ISSN 2041-1723, Vol. 6, article id 7028Article in journal (Refereed) Published
Abstract [en]

Unravelling how neurons are guided during vertebrate embryonic development has wide implications for understanding the assembly of the nervous system. During embryogenesis, migration of neuronal cell bodies and axons occurs simultaneously, but to what degree they influence each other's development remains obscure. We show here that within the mouse embryonic spinal cord, commissural axons bisect, delimit or preconfigure ventral interneuron cell body position. Furthermore, genetic disruption of commissural axons results in abnormal ventral interneuron cell body positioning. These data suggest that commissural axonal fascicles instruct cell body position by acting either as border landmarks (axon-restricted migration), which to our knowledge has not been previously addressed, or acting as cellular guides. This study in the developing spinal cord highlights an important function for the interaction of cell bodies and axons, and provides a conceptual proof of principle that is likely to have overarching implications for the development of neuronal architecture.

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urn:nbn:se:umu:diva-106511 (URN)10.1038/ncomms8028 (DOI)000355530100002 ()25960414 (PubMedID)
Available from: 2015-07-15 Created: 2015-07-14 Last updated: 2018-06-07Bibliographically approved
Open this publication in new window or tab >>Netrin 1 and Dcc signalling are required for confinement of central axons within the central nervous system
2014 (English)In: Development, ISSN 0950-1991, E-ISSN 1477-9129, Vol. 141, no 3, p. 594-603Article in journal (Refereed) Published
Abstract [en]

The establishment of anatomically stereotyped axonal projections is fundamental to neuronal function. While most neurons project their axons within the central nervous system (CNS), only axons of centrally born motoneurons and peripherally born sensory neurons link the CNS and peripheral nervous system (PNS) together by navigating through specialized CNS/PNS transition zones. Such selective restriction is of importance because inappropriate CNS axonal exit could lead to loss of correct connectivity and also to gain of erroneous functions. However, to date, surprisingly little is known about the molecular-genetic mechanisms that regulate how central axons are confined within the CNS during development. Here, we show that netrin 1/Dcc/Unc5 chemotropism contributes to axonal confinement within the CNS. In both Ntn1 and Dcc mutant mouse embryos, some spinal interneuronal axons exit the CNS by traversing the CNS/PNS transition zones normally reserved for motor and sensory axons. We provide evidence that netrin 1 signalling preserves CNS/PNS axonal integrity in three ways: (1) netrin 1/Dcc ventral attraction diverts axons away from potential exit points; (2) a Dcc/Unc5c-dependent netrin 1 chemoinhibitory barrier in the dorsolateral spinal cord prevents interneurons from being close to the dorsal CNS/PNS transition zone; and (3) a netrin 1/Dcc-dependent, Unc5c-independent mechanism that actively prevents exit from the CNS. Together, these findings provide insights into the molecular mechanisms that maintain CNS/PNS integrity and, to the best of our knowledge, present the first evidence that chemotropic signalling regulates interneuronal CNS axonal confinement in vertebrates.

Netrin 1, Dcc, Spinal cord, CNS exit, Unc5, Axonal confinement, Mouse
National Category
General Practice
urn:nbn:se:umu:diva-86827 (URN)10.1242/dev.099606 (DOI)000330573500011 ()
Available from: 2014-03-17 Created: 2014-03-11 Last updated: 2018-06-08Bibliographically approved

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