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ISDN2014_0139: Lineage tracing of neuronal progenitor cells expressing dlx genes in the zebrafish brain
Author(s) -
Solek Cynthia,
Feng Shengrui,
Mahoney Elyssa,
Ekker Marc
Publication year - 2015
Publication title -
international journal of developmental neuroscience
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.761
H-Index - 88
eISSN - 1873-474X
pISSN - 0736-5748
DOI - 10.1016/j.ijdevneu.2015.04.114
Subject(s) - library science , genomics , research center , zebrafish , biology , genetics , medicine , computer science , gene , genome , pathology
cuit integration timing is controlled to favor specific differentiation program. In cerebellar cortex, molecular layer GABAergic interneuron (MLGI) circuit comprises two cellular subtypes: the Basket and the Stellate cells. They display major morphological differences but present no discriminating genetic marker. It has been proposed that their morphological differences are due to substantially different developmental environments. However, due to persisting lack of evidence to support this view, the question has remained controversial. In this study we unravel stereotyped migration paths that could elicit the emergence of morphological differences. Our in vivo grafts experiments show that Basket and Stellate might use distinct migratory pathways during neuronal circuit integration. We conducted a series of time-lapse experiments on acute slices and uncovered that a proportion of immature MLGI penetrate the External Granule cell Layer (EGL) where they migrate tangentially during a restricted time period. We showed that this newly described tangential migration follows the trajectory of the elongating parallel fibers and can be induced or rerouted ex vivo. Using organo-graft experiments, we showed that tangentially migrating MLGI, ultimately, differentiated into stellate-like cells, and that the recipient environment largely conditions the proper course of this stereotyped differentiation program. To our knowledge, tangential migration of stellate-cells represents the first indication of an early divergence during basket versus stellate maturation process. Our data show that time-dependant environmental changes favor subsequent morphological specificities within a genetically homogeneous progenitor cell population. We propose here that stereotyped migration paths act as a cell diversity maker by specifically extending the maturation process of Stellate-cells thus delaying the onset of differentiation and consequently their local developmental environment.