Functional genomic analysis of the periodic transcriptome in the developing Drosophila wing [Affymetrix]

The eukaryotic cell cycle, driven by both transcriptional and post-translational mechanisms, is the central molecular oscillator underlying tissue growth throughout animals. While genome-wide studies have investigated cell cycle-associated transcription in unicellular systems, global patterns of periodic transcription in multicellular tissues remain largely unexplored. Here we define the cell cycle-associated transcriptome of the developing Drosophila wing epithelium and compare it with that of cultured Drosophila S2 cells, revealing a core set of periodic genes as well as a surprising degree of context-specificity in periodic transcription. We further employ RNAi-mediated phenotypic profiling to define functional requirements for over 300 periodic genes, with a focus on those required for cell proliferation in vivo. Finally, we investigate the role of novel genes required for interkinetic nuclear migration. Combined, these findings provide a global perspective on cell cycle control in vivo, and highlight a critical need to understand the context-specific regulation of cell proliferation. Cells from developing Drosophila wing epithelium, and cultured S2 cells are FACS sorted into G1 and G2 populations based on DNA content and compared in triplicate on Affymetrix microarrays to identify differences in the transcriptional program of the cell cycle by cell type.