Dissecting the Fat/Dachsous pathways role in planar cell polarity using chromatin immunoprecipitation to find targets of Atrophin. Kelvin Yeung^1,2, Helen McNeill^1,2. 1) Research, Samuel Lunenfeld Res Inst, Toronto, Ontario, Canada; 2) Molecular Genetics, University of Toronto St. George Campus, Toronto, Ontario, Canada.

   Planar cell polarity (PCP) is the phenomenon in which epithelial cells are polarized in the plane of the epithelium, orthogonal to the apicobasal axis. PCP is evident in several Drosophila tissues such as the orientation of hairs on the Drosophila wing and the proper rotation of photoreceptor clusters in the Drosophila eye. There are several signalling pathways that establish PCP; one of which is the Fat/Dachsous (Ft/Ds) signalling pathway. Atrophin (Atro, also known as Grunge) is a downstream component in the Ft/Ds pathway and Atro is a nuclear co-repressor. However the downstream target genes of Atro in the Ft/Ds pathway remain unknown. In order to identify Atros target genes that play a role in PCP, we plan to use chromatin immunoprecipitation (ChIP) against Atro followed by microarray in developing Drosophila embryos. To assess the PCP role(s) of the potential Atro targets, we plan to check the wings and eyes of RNA interference and mutant flies for PCP defects. To perform an Atro ChIP, I made and tested an anti-Atro antibody. I used my antibody to perform ChIPs in Drosophila S2 cells. End point PCR and quantitative PCR results showed that the ChIPs were successful as a known target of Atro was enriched when compared with the negative controls. I also carried out an Atro ChIP in embryos and verified it with end point PCR.