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[P93]: Co‐ordinate regulation of angiogenesis and neurogenesis in the embryonic telencephalon
Author(s) -
Vasudevan A.,
Bhide P.G.
Publication year - 2006
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.2006.09.155
Subject(s) - medical school , general hospital , citation , cerebrum , library science , neurogenesis , embryonic stem cell , medicine , computer science , psychology , neuroscience , pediatrics , medical education , biology , genetics , gene , central nervous system
Dlx genes are required for the differentiation and migration of cortical GABAergic interneurons derived from progenitors located in the medial ganglionic eminence (MGE) and perhaps the caudal ganglionic eminence (CGE). It is not clear how the diversity of GABAergic interneuron subtypes is established and if it involves distinct progenitors in the MGE and CGE. We have identified three conserved enhancers, URE2, I12b and I56i in the Dlx gene loci of vertebrates. All three target expression in cells of the forebrain where endogenous Dlx genes are expressed but show differences in their regional and temporal activities. We examined if such differences in Dlx enhancer activity could be associated to different progenitor populations. We compared the activity of the three enhancers in the MGE and CGE, and in migrating neurons derived from these regions between E11.5 and E13.5 using: (1) reporter lines under the control of each enhancer; (2) double immunohistochemistry on lines with two reporter genes driven by different enhancers. We compared the migration potential of progenitors found in different ventral structures using DiI labelling and co-transplantation experiments in vitro. We also co-labelled adult cortical interneurons in the URE2 and I12b lines, separately. URE2, I12b and I56i displayed differential activities in the dorsal MGE, ventral MGE and CGE, and labelled distinct populations of tangentially migrating neurons at E12.5 and E13.5. We provide evidence that the dMGE and vMGE are distinct sources of tangentially migrating neurons at these ages. In the adult cortex, URE2 labelled the parvalbumin-, calretinin-, NPYand nNOS-positive interneurons, whereas I12b was active in subpopulations of these groups and marked specifically the somatostatinand VIP-positive interneurons. Dlx gene regulation conferred by several enhancers provides molecular evidence that regional specification of progenitors located in subdivisions within the MGE and CGE generate different subtypes of cortical interneurons in the adult brain.