title: unfulfilled interacting genes display branch-specific roles in the development of mushroom body axons in Drosophila melanogaster.
abstract: The mushroom body (MB) of Drosophila melanogaster is an organized collection of interneurons that is required for learning and memory. Each of the three subtypes of MB neurons, γ, α'/β', and α/β, branch at some point during their development, providing an excellent model in which to study the genetic regulation of axon branching. Given the sequential birth order and the unique patterning of MB neurons, it is likely that specific gene cascades are required for the different guidance events that form the characteristic lobes of the MB. The nuclear receptor UNFULFILLED (UNF), a transcription factor, is required for the differentiation of all MB neurons. We have developed and used a classical genetic suppressor screen that takes advantage of the fact that ectopic expression of unf causes lethality to identify candidate genes that act downstream of UNF. We hypothesized that reducing the copy number of unf-interacting genes will suppress the unf-induced lethality. We have identified 19 candidate genes that when mutated suppress the unf-induced lethality. To test whether candidate genes impact MB development, we performed a secondary phenotypic screen in which the morphologies of the MBs in animals heterozygous for unf and a specific candidate gene were analyzed. Medial MB lobes were thin, missing, or misguided dorsally in five double heterozygote combinations (;unf/+;axin/+, unf/+;Fps85D/+, ;unf/+;Tsc1/+, ;unf/+;Rheb/+, ;unf/+;msn/+). Dorsal MB lobes were missing in ;unf/+;DopR2/+ or misprojecting beyond the termination point in ;unf/+;Sytβ double heterozygotes. These data suggest that unf and unf-interacting genes play specific roles in axon development in a branch-specific manner.
authors.affiliation: Department of Biology, University of Hawaii, Honolulu, Hawaii 96822.
authors.forename: Karen E
authors.initials: KE
authors.lastname: Bates
authors.forename: Carl
authors.initials: C
authors.lastname: Sung
authors.forename: Liam
authors.initials: L
authors.lastname: Hilson
authors.forename: Steven
authors.initials: S
authors.lastname: Robinow
mesh_terms: D000818:Animals; D001369:Axons / Q000378:metabolism*; D029721:Drosophila Proteins / Q000235:genetics / Q000378:metabolism; D004331:Drosophila melanogaster / Q000196:embryology / Q000254:growth & development / Q000378:metabolism*; D005838:Genotype; D006579:Heterozygote; D007150:Immunohistochemistry; D024521:Mushroom Bodies / Q000196:embryology / Q000254:growth & development / Q000378:metabolism*; D009474:Neurons / Q000378:metabolism; D018160:Receptors, Cytoplasmic and Nuclear / Q000235:genetics / Q000378:metabolism; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism
chemical_list: D029721:Drosophila Proteins; D018160:Receptors, Cytoplasmic and Nuclear; D014157:Transcription Factors
keywords: CG16801; dHR51; neuronal differentiation; nuclear receptor; suppressor screen