title: Transcriptional regulatory mechanisms underlying the GABAergic neuron fate in different diencephalic prosomeres.
abstract: Diverse mechanisms regulate development of GABAergic neurons in different regions of the central nervous system. We have addressed the roles of a proneural gene, Ascl1, and a postmitotic selector gene, Gata2, in the differentiation of GABAergic neuron subpopulations in three diencephalic prosomeres: prethalamus (P3), thalamus (P2) and pretectum (P1). Although the different proliferative progenitor populations of GABAergic neurons commonly express Ascl1, they have distinct requirements for it in promotion of cell-cycle exit and GABAergic neuron identity. Subsequently, Gata2 is activated as postmitotic GABAergic precursors are born. In P1, Gata2 regulates the neurotransmitter identity by promoting GABAergic and inhibiting glutamatergic neuron differentiation. Interestingly, Gata2 defines instead the subtype of GABAergic neurons in the rostral thalamus (pTh-R), which is a subpopulation of P2. Without Gata2, the GABAergic precursors born in the pTh-R fail to activate subtype-specific markers, but start to express genes typical of GABAergic precursors in the neighbouring P3 domain. Thus, our results demonstrate diverse mechanisms regulating differentiation of GABAergic neuron subpopulations and suggest a role for Gata2 as a selector gene of both GABAergic neuron neurotransmitter and prosomere subtype identities in the developing diencephalon. Our results demonstrate for the first time that neuronal identities between distinct prosomeres can still be transformed in postmitotic neuronal precursors.
authors.affiliation: Department of Biosciences and Institute of Biotechnology, Viikki Biocenter, PO Box 56, Viikinkaari 5, FIN00014-University of Helsinki, Helsinki,  Finland.
authors.forename: Sini-Maaria
authors.initials: SM
authors.lastname: Virolainen
authors.forename: Kaia
authors.initials: K
authors.lastname: Achim
authors.forename: Paula
authors.initials: P
authors.lastname: Peltopuro
authors.forename: Marjo
authors.initials: M
authors.lastname: Salminen
authors.forename: Juha
authors.initials: J
authors.lastname: Partanen
mesh_terms: D000818:Animals; D051792:Basic Helix-Loop-Helix Proteins / Q000235:genetics / Q000378:metabolism*; D001921:Brain / Q000196:embryology; D002454:Cell Differentiation; D004027:Diencephalon / Q000166:cytology / Q000196:embryology*; D059330:GABAergic Neurons / Q000378:metabolism*; D050989:GATA2 Transcription Factor / Q000235:genetics / Q000378:metabolism*; D050990:GATA3 Transcription Factor / Q000096:biosynthesis / Q000235:genetics; D018507:Gene Expression Regulation, Developmental; D051379:Mice; D008822:Mice, Transgenic; D055495:Neurogenesis; D013788:Thalamus / Q000166:cytology / Q000196:embryology; D015533:Transcriptional Activation
chemical_list: D051792:Basic Helix-Loop-Helix Proteins; D050989:GATA2 Transcription Factor; D050990:GATA3 Transcription Factor; C499317:Ascl1 protein, mouse; C494712:Gata2 protein, mouse; C494748:Gata3 protein, mouse