title: Genome wide analysis of transcript levels after perturbation of the EGFR pathway in the Drosophila ovary.
abstract: Defects in the epidermal growth factor receptor (EGFR) pathway can lead to aggressive tumor formation. Activation of this pathway during normal development produces multiple outcomes at the cellular level, leading to cellular differentiation and cell cycle activation. To elucidate the downstream events induced by this pathway, we used genome-wide cDNA microarray technology to identify potential EGFR targets in Drosophila oogenesis. We focused on genes for which the transcriptional responses due to EGFR pathway activation and inactivation were in opposite directions, as this is expected for genes that are directly regulated by the pathway in this tissue type. We perturbed the EGFR pathway in epithelial follicle cells using seven different genetic backgrounds. To activate the pathway, we overexpressed an activated form of the EGFR (UAS-caEGFR), and an activated form of the signal transducer Raf (UAS-caRaf); we also over- or ectopically expressed the downstream homeobox transcription factor Mirror (UAS-mirr) and the ligand-activating serine protease Rhomboid (UAS-rho). To reduce pathway activity we used loss-of-function mutations in the ligand (gurken) and receptor (torpedo). From microarrays containing 6,255 genes, we found 454 genes that responded in an opposite manner in gain-of-function and loss-of-function conditions among which are many Wingless signaling pathway components. Further analysis of two such components, sugarless and pangolin, revealed a function for these genes in late follicle cell patterning. Of interest, components of other signaling pathways were also enriched in the EGFR target group, suggesting that one reason for the pleiotropic effects seen with EGFR activity in cancer progression and development may be its ability to regulate many other signaling pathways.
authors.affiliation: Department of Biochemistry, University of Washington, Seattle, Washington 98195-7350, USA.
authors.forename: Katherine C
authors.initials: KC
authors.lastname: Jordan
authors.forename: Steven D
authors.initials: SD
authors.lastname: Hatfield
authors.forename: Michael
authors.initials: M
authors.lastname: Tworoger
authors.forename: Ellen J
authors.initials: EJ
authors.lastname: Ward
authors.forename: Karin A
authors.initials: KA
authors.lastname: Fischer
authors.forename: Stuart
authors.initials: S
authors.lastname: Bowers
authors.forename: Hannele
authors.initials: H
authors.lastname: Ruohola-Baker
mesh_terms: D000818:Animals; D004330:Drosophila / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D029721:Drosophila Proteins / Q000235:genetics / Q000378:metabolism; D066246:ErbB Receptors / Q000378:metabolism*; D005136:Eye Proteins / Q000235:genetics / Q000378:metabolism; D005260:Female; D020869:Gene Expression Profiling; D016678:Genome; D018398:Homeodomain Proteins / Q000235:genetics / Q000378:metabolism; D007150:Immunohistochemistry; D017403:In Situ Hybridization; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism; D008954:Models, Biological; D009154:Mutation; D020411:Oligonucleotide Array Sequence Analysis; D009866:Oogenesis; D010053:Ovary / Q000166:cytology / Q000378:metabolism*; D011518:Proto-Oncogene Proteins / Q000378:metabolism; D012097:Repressor Proteins / Q000378:metabolism; D015398:Signal Transduction; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism; D016211:Transforming Growth Factor alpha / Q000235:genetics / Q000378:metabolism; D051155:Wnt1 Protein; D048490:raf Kinases / Q000378:metabolism
chemical_list: D029721:Drosophila Proteins; D005136:Eye Proteins; D018398:Homeodomain Proteins; D008565:Membrane Proteins; D011518:Proto-Oncogene Proteins; D012097:Repressor Proteins; C081481:Rho protein, Drosophila; D014157:Transcription Factors; D016211:Transforming Growth Factor alpha; D051155:Wnt1 Protein; C083730:grk protein, Drosophila; C105790:mirr protein, Drosophila; C115159:pan protein, Drosophila; C074622:wg protein, Drosophila; D066246:ErbB Receptors; D048490:raf Kinases