Drosophila egg chambers: control vs. ectopic JAK/STAT and EGFR signaling

During Drosophila melanogaster oogenesis, the JAK/STAT and EGFR pathways are both required to specify a population of somatic epithelial cells called the posterior follicle cells (PFCs). The PFCs are important because they generate a signal at mid-oogenesis that is required to establish the embryonic axes. To identify novel PFC-expressed transcripts, egg chambers containing ectopic PFCs were generated and microarrays were then used to identify upregulated transcripts. To generate ectopic PFCs, GAL80TS / CyO ; UAS-Upd, UAS-λtorpedo/TM6B flies were crossed to GR1-GAL4 flies to obtain the genotype GAL80TS/+ ; GR1-GAL4/UAS-Unpaired, UAS-λtorpedo. Sibling females of genotype GAL80TS/+ ; GR1-GAL4/TM6B were dissected as controls. A reference design was used to control for dye bias in a two-color experiment. Reference (WT) RNA was isolated from the ovaries of OreR flies. Experimental RNA was isolated from the ovaries of 5-8 day old flies of genotype GAL80TS/+ ; GR1-GAL4/UAS-Unpaired, UAS-λtorpedo and control RNA from ovaries of 5-8 day old flies of genotype GAL80TS/+ ; GR1-GAL4/TM6B. Three biological replicates each were performed for the experimental and control conditions. A total of 6 arrays were used. Experimental and control RNA was labeled with Cy5 and universal common reference RNA with Cy3.