title: Ras1-mediated modulation of Drosophila homeotic function in cell and segment identity.
abstract: Mutations of the Drosophila homeotic proboscipedia gene (pb, the Hox-A2/B2 homologue) provoke dose-sensitive defects. These were used to search for dose-sensitive dominant modifiers of pb function. Two identified interacting genes were the proto-oncogene Ras1 and its functional antagonist Gap1, prominent intermediaries in known signal transduction pathways. Ras1+ is a positive modifier of pb activity both in normal and ectopic cell contexts, while the Ras1-antagonist Gap1 has an opposite effect. A general role for Ras1 in homeotic function is likely, since Ras1+ activity also modulates functions of the homeotic loci Sex combs reduced and Ultrabithorax. Our data suggest that the modulation occurs by a mechanism independent of transcriptional control of the homeotic loci themselves, or of the Ras1/Gap1 genes. Taken together our data support a role for Ras1-mediated cell signaling in the homeotic control of segmental differentiation.
authors.affiliation: CBD-CNRS, Toulouse, France.
authors.forename: M
authors.initials: M
authors.lastname: Boube
authors.forename: C
authors.initials: C
authors.lastname: Benassayag
authors.forename: L
authors.initials: L
authors.lastname: Seroude
authors.forename: D L
authors.initials: DL
authors.lastname: Cribbs
mesh_terms: D000818:Animals; D030801:Animals, Genetically Modified; D019521:Body Patterning; D004331:Drosophila melanogaster / Q000033:anatomy & histology / Q000235:genetics* / Q000254:growth & development*; D020690:GTPase-Activating Proteins; D018507:Gene Expression Regulation, Developmental; D005801:Genes, Homeobox; D017344:Genes, Insect; D011905:Genes, ras; D017403:In Situ Hybridization; D009154:Mutation; D010641:Phenotype; D011506:Proteins / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction; D014158:Transcription, Genetic; D020703:ras GTPase-Activating Proteins; D018631:ras Proteins / Q000378:metabolism
chemical_list: D020690:GTPase-Activating Proteins; D011506:Proteins; D020703:ras GTPase-Activating Proteins; D018631:ras Proteins