Expression data from third instar Drosophila eye discs

Third instar larval eye discs provide an in vivo model for cell cycle exit studies. Posterior to the Second Mitotic Wave proliferation is absent in a wild type eye disc. Inactivating mutations in tumor suppressor-like genes can lead to genome wide changes in gene expression that allow for inappropriate bypass of cell cycle exit signals posterior to the Second Mitotic Wave. In a mosaic tissue comprised of two wild type (Canton) populations (distinguished by presence or absence of GFP) there is roughly a 50/50 distribution of both populations in the tissue. Using the same method but comparing Warts (wts) to wild type you see that Warts mutant tissue is ~70-80% of the eye disc and the rest is wild type tissue. In the comparison of rbf1120a v rbf1120a+wts using the same method for mosaic creation we were able to see a similar ~80-85% of the eye disc as rbf1120a+wts. rbf1120a cells have relatively little advantage over wild type cells, but we were able to use entirely homozygous mutant discs for RNA extraction. We used microarrays to detail the global program of gene expression underlying cell cycle exit and identified distinct classes of up-regulated and down-regulated genes during this process. Drosophila third instar larvea were selected and the eye discs from these animals were prepared for RNA extraction and hybridization on Affymetrix microarrays. We used mosaic larval discs but the majority of the tissue was comprised of the mutant allelic combination we desired due to the proliferative advantage of these mutant cells over wild type cells.