Switching cell fates in the developing Drosophila eye.
The developing Drosophila ommatidium is characterized by two distinct waves of pattern formation. In the first wave, a precluster of five cells is formed by a complex cellular interaction mechanism. In the second wave, cells are systematically recruited to the cluster and directed to their fates by developmental cues presented by differentiating precluster cells. These developmental cues are mediated through the receptor tyrosine kinase (RTK) and Notch (N) signaling pathways and their combined activities are crucial in specifying cell type. The transcription factor Lozenge (Lz) is expressed exclusively in second wave cells. Here, we ectopically supply Lz to precluster cells and concomitantly supply the various RTK/N codes that specify each of three second wave cell fates. We thereby reproduce molecular markers of each of the second wave cell types in precluster cells and draw three inferences. First, we confirm that Lz provides key intrinsic information to second wave cells. We can now combine this with the RTK/N signaling to provide a cell fate specification code that entails both extrinsic and intrinsic information. Second, the reproduction of each second wave cell type in the precluster confirms the accuracy of the RTK/N signaling code. Third, RTK/N signaling and Lz need only be presented to the cells for a short period of time in order to specify their fate.
Department of Genetics and Development, College of Physicians and Surgeons, Columbia University, 701 West 168th Street, New York, NY 10032, USA.
Yannis Emmanuel
YE
Mavromatakis
Andrew
A
Tomlinson
D000818:Animals; D002454:Cell Differentiation / Q000502:physiology*; D054910:Compound Eye, Arthropod / Q000166:cytology / Q000254:growth & development*; D004268:DNA-Binding Proteins / Q000378:metabolism* / Q000494:pharmacology; D004330:Drosophila / Q000254:growth & development*; D029721:Drosophila Proteins / Q000378:metabolism* / Q000494:pharmacology; D006652:Histological Techniques; D007150:Immunohistochemistry; D007814:Larva / Q000254:growth & development; D020794:Receptor Protein-Tyrosine Kinases / Q000378:metabolism*; D051880:Receptors, Notch / Q000378:metabolism*; D015398:Signal Transduction / Q000502:physiology*; D014157:Transcription Factors / Q000378:metabolism* / Q000494:pharmacology
D004268:DNA-Binding Proteins; D029721:Drosophila Proteins; C497759:N protein, Drosophila; D051880:Receptors, Notch; D014157:Transcription Factors; C099964:lz protein, Drosophila; D020794:Receptor Protein-Tyrosine Kinases
Cell fate; Drosophila; Eye; Lozenge; R7