title: Ligand-independent activation of the sevenless receptor tyrosine kinase changes the fate of cells in the developing Drosophila eye.
abstract: Cell fate in the developing eye is determined by a cascade of inductive interactions. In this process, the sevenless protein--a receptor tyrosine kinase--is required for the specification of the R7 photoreceptor cell fate. We have constructed a gain-of-function sevenless mutation (SevS11) by overexpressing a truncated sevenless protein in the cells where sevenless is normally expressed. In SevS11 mutant flies, all sevenless-expressing cells initiate neural development. This results in the formation of multiple R7-like photoreceptors per ommatidium. Therefore, sevenless activity appears to be necessary and sufficient for the determination of R7 cell fate. These results illustrate the central role receptor tyrosine kinases can play in the specification of cell fate during development.
authors.affiliation: Zoologisches Institut, Universität Zürich, Switzerland.
authors.forename: K
authors.initials: K
authors.lastname: Basler
authors.forename: B
authors.initials: B
authors.lastname: Christen
authors.forename: E
authors.initials: E
authors.lastname: Hafen
mesh_terms: D000818:Animals; D001483:Base Sequence; D004330:Drosophila / Q000196:embryology* / Q000235:genetics; D029721:Drosophila Proteins; D004742:Enhancer Elements, Genetic / Q000235:genetics; D005123:Eye / Q000196:embryology; D005136:Eye Proteins / Q000502:physiology*; D005786:Gene Expression Regulation / Q000502:physiology; D005796:Genes; D008562:Membrane Glycoproteins; D008565:Membrane Proteins / Q000502:physiology*; D008969:Molecular Sequence Data; D005810:Multigene Family; D016296:Mutagenesis; D009474:Neurons / Q000166:cytology; D010786:Photoreceptor Cells / Q000196:embryology; D011505:Protein-Tyrosine Kinases / Q000235:genetics; D020794:Receptor Protein-Tyrosine Kinases; D013234:Stem Cells / Q000166:cytology / Q000201:enzymology
chemical_list: D029721:Drosophila Proteins; D005136:Eye Proteins; D008562:Membrane Glycoproteins; D008565:Membrane Proteins; D011505:Protein-Tyrosine Kinases; D020794:Receptor Protein-Tyrosine Kinases; C056737:sev protein, Drosophila