Terminal glial differentiation involves regulated expression of the excitatory amino acid transporters in the Drosophila embryonic CNS.
The Drosophila excitatory amino acid transporters dEAAT1 and dEAAT2 are nervous-specific transmembrane proteins that mediate the high affinity uptake of L-glutamate or aspartate into cells. Here, we demonstrate by colocalization studies that both genes are expressed in discrete and partially overlapping subsets of differentiated glia and not in neurons in the embryonic central nervous system (CNS). We show that expression of these transporters is disrupted in mutant embryos deficient for the glial fate genes glial cells missing (gcm) and reversed polarity (repo). Conversely, ectopic expression of gcm in neuroblasts, which forces all nerve cells to adopt a glial fate, induces an ubiquitous expression of both EAAT genes in the nervous system. We also detected the dEAAT transcripts in the midline glia in late embryos and dEAAT2 in a few peripheral neurons in head sensory organs. Our results show that glia play a major role in excitatory amino acid transport in the Drosophila CNS and that regulated expression of the dEAAT genes contributes to generate the functional diversity of glial cells during embryonic development.
Soustelle
Laurent
L
Laboratoire de Génétique et Physiologie du Développement, CNRS-Université de la Méditerranée, Developmental Biology Institute of Marseille, Campus de Luminy case 907, 13288 Marseille Cedex 09, France .
Besson
Marie-Thérèse
MT
Rival
Thomas
T
Birman
Serge
S
D000818:Animals; D002454:Cell Differentiation; D002490:Central Nervous System / Q000196:embryology*; D004268:DNA-Binding Proteins; D004330:Drosophila / Q000196:embryology* / Q000235:genetics; D029721:Drosophila Proteins / Q000378:metabolism*; D027341:Excitatory Amino Acid Transporter 1 / Q000378:metabolism*; D027342:Excitatory Amino Acid Transporter 2 / Q000378:metabolism*; D018846:Excitatory Amino Acids / Q000378:metabolism*; D020869:Gene Expression Profiling; D018507:Gene Expression Regulation, Developmental; D018398:Homeodomain Proteins / Q000378:metabolism; D017403:In Situ Hybridization; D009457:Neuroglia / Q000166:cytology* / Q000378:metabolism; D009479:Neuropeptides / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D015534:Trans-Activators / Q000235:genetics / Q000378:metabolism; D014157:Transcription Factors
D004268:DNA-Binding Proteins; D029721:Drosophila Proteins; C421004:Eaat2 protein, Drosophila; D027341:Excitatory Amino Acid Transporter 1; D027342:Excitatory Amino Acid Transporter 2; D018846:Excitatory Amino Acids; C102805:GCM protein, Drosophila; D018398:Homeodomain Proteins; D009479:Neuropeptides; D012333:RNA, Messenger; D015534:Trans-Activators; D014157:Transcription Factors; C089972:repo protein, Drosophila