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1.  Insights to transcriptional networks by using high throughput RNAi strategies 
RNA interference (RNAi) is a powerful method to unravel the role of a given gene in eukaryotic cells. The development of high throughput assay platforms such as fluorescence plate readers and high throughput microscopy has allowed the design of genome wide RNAi screens to systemically discern members of regulatory networks around various cellular processes. Here we summarize the different strategies employed in RNAi screens to reveal regulators of transcriptional networks. We focus our discussion in experimental approaches designed to uncover regulatory interactions modulating transcription factor activity.
PMCID: PMC3097102  PMID: 19952073
RNAi screen; transcription factor; reporter; localization; post-translational modification
2.  Drosophila FoxO Regulates Organism Size and Stress Resistance through an Adenylate Cyclase▿ † 
Molecular and Cellular Biology  2009;29(19):5357-5365.
Forkhead box class O (FoxO) transcription factors are a family of conserved proteins that regulate the cellular responses to various stimuli, such as energy deprivation, stress, and developmental cues. FoxO proteins are important mediators of the insulin signaling pathway, adjusting growth and metabolism to nutrient availability. Insulin signaling acts together with the glucagon-stimulated cAMP signaling pathway to orchestrate the organism response to various nutritional conditions. In this study, we demonstrate that Drosophila melanogaster FoxO (dFoxO) regulates cAMP signaling by directly inducing the expression of an adenylate cyclase gene, ac76e. Interestingly, ac76e is expressed in a highly restricted pattern throughout fly development, limited to the corpus allatum (CA), gastric cecum, and malpighian tubules. dFoxO activation of AC76E in the CA increases starvation resistance and limits growth. Our results unravel a new role for dFoxO, integrating cAMP and insulin signaling to adapt organism growth to the existing nutritional conditions.
PMCID: PMC2747984  PMID: 19651894
3.  FOXO-regulated transcription restricts overgrowth of Tsc mutant organs 
The Journal of Cell Biology  2008;180(4):691-696.
FOXO is thought to function as a repressor of growth that is, in turn, inhibited by insulin signaling. However, inactivating mutations in Drosophila melanogaster FOXO result in viable flies of normal size, which raises a question over the involvement of FOXO in growth regulation. Previously, a growth-suppressive role for FOXO under conditions of increased target of rapamycin (TOR) pathway activity was described. Here, we further characterize this phenomenon. We show that tuberous sclerosis complex 1 mutations cause increased FOXO levels, resulting in elevated expression of FOXO-regulated genes, some of which are known to antagonize growth-promoting pathways. Analogous transcriptional changes are observed in mammalian cells, which implies that FOXO attenuates TOR-driven growth in diverse species.
PMCID: PMC2265581  PMID: 18299344

Results 1-3 (3)