title: Huckebein-mediated autoregulation of Glide/Gcm triggers glia specification.
abstract: Cell specification in the nervous system requires patterning genes dictating spatio-temporal coordinates as well as fate determinants. In the case of neurons, which are controlled by the family of proneural transcription factors, binding specificity and patterned expression trigger both differentiation and specification. In contrast, a single gene, glide cell deficient/glial cell missing (glide/gcm), is sufficient for all fly lateral glial differentiation. How can different types of cells develop in the presence of a single fate determinant, that is, how do differentiation and specification pathways integrate and produce distinct glial populations is not known. By following an identified lineage, we here show that glia specification is triggered by high glide/gcm expression levels, mediated by cell-specific protein-protein interactions. Huckebein (Hkb), a lineage-specific factor, provides a molecular link between glide/gcm and positional cues. Importantly, Hkb does not activate transcription; rather, it physically interacts with Glide/Gcm thereby triggering its autoregulation. These data emphasize the importance of fate determinant cell-specific quantitative regulation in the establishment of cell diversity.
authors.affiliation: Institut de Génétique et de Biologie Moléculaire et Cellulaire, CNRS/INSERM/ULP, Illkirch Cedex, CU de Strasbourg, France.
authors.forename: Rossana
authors.initials: R
authors.lastname: De Iaco
authors.forename: Laurent
authors.initials: L
authors.lastname: Soustelle
authors.forename: Martial
authors.initials: M
authors.lastname: Kammerer
authors.forename: Sandro
authors.initials: S
authors.lastname: Sorrentino
authors.forename: Cécile
authors.initials: C
authors.lastname: Jacques
authors.forename: Angela
authors.initials: A
authors.lastname: Giangrande
mesh_terms: D000818:Animals; D001483:Base Sequence; D002454:Cell Differentiation / Q000235:genetics; D019070:Cell Lineage; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D029721:Drosophila Proteins / Q000235:genetics / Q000378:metabolism*; D004331:Drosophila melanogaster / Q000166:cytology / Q000196:embryology* / Q000235:genetics; D006706:Homeostasis; D008969:Molecular Sequence Data; D009457:Neuroglia / Q000166:cytology*; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*; D014158:Transcription, Genetic; D015854:Up-Regulation
chemical_list: D004268:DNA-Binding Proteins; D029721:Drosophila Proteins; C102805:GCM protein, Drosophila; C087725:Hkb protein, Drosophila; D014157:Transcription Factors