title: Lineage, migration, and morphogenesis of longitudinal glia in the Drosophila CNS as revealed by a molecular lineage marker.
abstract: Previous studies described three different classes of glial cells in the developing CNS of the early Drosophila embryo that prefigure and ensheath the major CNS axon tracts. Among these are 6 longitudinal glial cells on each side of each segment that overlie the longitudinal axon tracts. Here we use transformant lines carrying a P element containing a 130 bp sequence from the fushi tarazu gene in front of the lacZ reporter gene to direct beta-galactosidase expression in the longitudinal glia. Using this molecular lineage marker, we show that 1 of the "neuroblasts" in each hemisegment is actually a glioblast, which divides once symmetrically, in contrast to the typical asymmetric neuroblast divisions, producing 2 glial cells, which migrate medially and divide to generate the 6 longitudinal glial cells. As with neuroblasts, mutations in Notch and other neurogenic genes lead to supernumerary glioblasts. The results indicate that the glioblast is similar to other neuroblasts; however, the positionally specified fate of this blast cell is to generate a specific lineage of glia rather than a specific family of neurons.
authors.affiliation: Howard Hughes Medical Institute, Department of Biochemistry, University of California, Berkeley 94720.
authors.forename: J R
authors.initials: JR
authors.lastname: Jacobs
authors.forename: Y
authors.initials: Y
authors.lastname: Hiromi
authors.forename: N H
authors.initials: NH
authors.lastname: Patel
authors.forename: C S
authors.initials: CS
authors.lastname: Goodman
mesh_terms: D000818:Animals; D015415:Biomarkers / Q000032:analysis*; D002455:Cell Division; D002465:Cell Movement; D002490:Central Nervous System / Q000166:cytology / Q000196:embryology*; D004331:Drosophila melanogaster / Q000196:embryology* / Q000235:genetics; D015870:Gene Expression; D005801:Genes, Homeobox; D009024:Morphogenesis; D009154:Mutation; D009457:Neuroglia / Q000032:analysis / Q000166:cytology*; D011993:Recombinant Fusion Proteins / Q000032:analysis; D013234:Stem Cells / Q000032:analysis / Q000166:cytology*
chemical_list: D015415:Biomarkers; D011993:Recombinant Fusion Proteins