Transcriptional regulation of glial cell specification.
Neuronal differentiation relies on proneural factors that also integrate positional information and contribute to the specification of the neuronal type. The molecular pathway triggering glial specification is not understood yet. In Drosophila, all lateral glial precursors and glial-promoting activity have been identified, which provides us with a unique opportunity to dissect the regulatory pathways controlling glial differentiation and specification. Although glial lineages are very heterogeneous with respect to position, time of differentiation, and lineage tree, they all express and require two homologous genes, glial cell deficient/glial cell missing (glide/gcm) and glide2, that act in concert, with glide/gcm constituting the major glial-promoting factor. Here, we show that glial specification resides in glide/gcm transcriptional regulation. The glide/gcm promoter contains lineage-specific elements as well as quantitative and turmoil elements scattered throughout several kilobases. Interestingly, there is no correlation between a specific regulatory element and the type of glial lineage. Thus, the glial-promoting factor acts as a naive switch-on button that triggers gliogenesis in response to multiple pathways converging onto its promoter. Both negative and positive regulation are required to control glide/gcm expression, indicating that gliogenesis is actively repressed in some neural lineages.
Ragone
Gianluca
G
Institut de Génétique et Biologie Moléculaire et Cellulaire, IGBMC/CNRS/ULP/INSERM - BP 10142 67404 Illkirch, c.u., de Strasbourg, France.
Van De Bor
Véronique
V
Sorrentino
Sandro
S
Kammerer
Martial
M
Galy
Anne
A
Schenck
Annette
A
Bernardoni
Roberto
R
Miller
Alita A
AA
Roy
Nivedita
N
Giangrande
Angela
A
D000818:Animals; D001369:Axons / Q000473:pathology; D001483:Base Sequence; D015415:Biomarkers; D002454:Cell Differentiation; D019070:Cell Lineage; D002490:Central Nervous System / Q000166:cytology* / Q000196:embryology*; D004330:Drosophila / Q000196:embryology / Q000235:genetics*; D004625:Embryo, Nonmammalian; D018507:Gene Expression Regulation, Developmental; D017344:Genes, Insect; D006720:Homozygote; D008959:Models, Neurological; D009154:Mutation; D009457:Neuroglia / Q000166:cytology*; D010641:Phenotype; D011401:Promoter Regions, Genetic; D013234:Stem Cells / Q000166:cytology; D013997:Time Factors; D014158:Transcription, Genetic; D019076:Transgenes
D015415:Biomarkers