Scabrous overexpression in the eye affects R3/R4 cell fate specification and inhibits notch signaling.
BACKGROUND
Planar cell polarity (PCP) in the Drosophila eye is generated when immature ommatidial preclusters acquire opposite chirality in the dorsal and ventral halves of the eye imaginal disc and rotate 90 ° toward the equator. The scabrous (sca) gene is involved in R8 differentiation and in the correct spacing of ommatidial clusters in eye imaginal discs, but it was also suggested to be required during ommatidial rotation. However, no clear relationships between sca and other genes involved in the process were established.


RESULTS
To explore the role of Sca in PCP establishment, we performed an RNAi-based modifier genetic screen using the rough eye phenotype of sca-overexpressing flies. We found that sca overexpression mainly affects R3/R4 cell specification as it was reported in Notch mutants. Of the 86 modifiers identified in the screen, genes encoding components of Notch signaling and proteins involved in intracellular transport were of particular interest.


CONCLUSIONS
These and other results obtained with a reporter line of Notch activity indicate that sca overexpression antagonizes Notch signaling in the Drosophila eye, and are inconsistent with Sca being an ommatidial rotation-specific factor. We also found that microtubule motors and other proteins involved in intracellular transport are related with Sca function.
Departamento de Genética, Facultad CC Biológicas, Universidad de Valencia, Burjasot, Spain.|Estructura de Recerca Interdisciplinar en Biotecnologia i Biomedicina (ERI BIOTECMED), Universidad de Valencia, Burjasot, Spain.
Verónica
V
Muñoz-Soriano
Departamento de Genética, Facultad CC Biológicas, Universidad de Valencia, Burjasot, Spain.
Diego
D
Santos
Estructura de Recerca Interdisciplinar en Biotecnologia i Biomedicina (ERI BIOTECMED), Universidad de Valencia, Burjasot, Spain.
Fabrice C
FC
Durupt
Departamento de Genética, Facultad CC Biológicas, Universidad de Valencia, Burjasot, Spain.
Sandra
S
Casani
Departamento de Genética, Facultad CC Biológicas, Universidad de Valencia, Burjasot, Spain.|Estructura de Recerca Interdisciplinar en Biotecnologia i Biomedicina (ERI BIOTECMED), Universidad de Valencia, Burjasot, Spain.
Nuria
N
Paricio
D000818:Animals; D030801:Animals, Genetically Modified; D002454:Cell Differentiation; D019070:Cell Lineage / Q000235:genetics*; D054910:Compound Eye, Arthropod / Q000378:metabolism*; D029721:Drosophila Proteins / Q000235:genetics* / Q000378:metabolism; D004331:Drosophila melanogaster; D006023:Glycoproteins / Q000235:genetics* / Q000378:metabolism; D010641:Phenotype; D051880:Receptors, Notch / Q000378:metabolism*; D015398:Signal Transduction / Q000235:genetics*
D029721:Drosophila Proteins; D006023:Glycoproteins; D051880:Receptors, Notch; C066579:sca protein, Drosophila
Drosophila; dominant modifiers; genetic screen; intracellular trafficking; planar cell polarity; symmetrical ommatidia