The atypical cadherin Flamingo links Frizzled and Notch signaling in planar polarity establishment in the Drosophila eye.
Planar cell polarity is established in the Drosophila eye through distinct fate specification of photoreceptors R3 and R4 by a two-tiered mechanism employing Fz and Notch signaling: Fz signaling specifies R3 and induces Dl to activate Notch in R4. We show that the atypical cadherin Flamingo (Fmi) plays critical, but distinct, roles in both R3 and R4. Fmi is first enriched at equatorial cell borders of R3/R4, positively interacting with Fz/Dsh. Subsequently, Fmi is upregulated in R4 by Notch and functions to downregulate Dl expression by antagonizing Fz signaling. This in turn amplifies and enforces the initial Fz-signaling bias in the R3/R4 pair. Our results reveal differences in the planar cell polarity genetic circuitry between the eye and the wing.
Das
Gishnu
G
Department of Molecular, Cell and Developmental Biology, Mount Sinai School of Medicine, One Gustave L. Levy Place, New York, NY 10029, USA.
Reynolds-Kenneally
Jessica
J
Mlodzik
Marek
M
D000818:Animals; D019521:Body Patterning; D015820:Cadherins / Q000235:genetics / Q000502:physiology*; D004330:Drosophila / Q000235:genetics / Q000254:growth & development* / Q000502:physiology; D029721:Drosophila Proteins / Q000235:genetics / Q000502:physiology*; D005123:Eye / Q000254:growth & development*; D051157:Frizzled Receptors; D018507:Gene Expression Regulation, Developmental; D008565:Membrane Proteins / Q000235:genetics / Q000502:physiology*; D009154:Mutation; D010641:Phenotype; D017956:Photoreceptor Cells, Invertebrate / Q000254:growth & development; D043562:Receptors, G-Protein-Coupled; D051880:Receptors, Notch; D015398:Signal Transduction; D014921:Wings, Animal / Q000254:growth & development
D015820:Cadherins; D029721:Drosophila Proteins; D051157:Frizzled Receptors; D008565:Membrane Proteins; C497759:N protein, Drosophila; D043562:Receptors, G-Protein-Coupled; D051880:Receptors, Notch; C058784:fz protein, Drosophila; C121420:stan protein, Drosophila