title: EGFR-dependent downregulation of Capicua and the establishment of Drosophila dorsoventral polarity.
abstract: Dorsoventral (DV) axis formation in Drosophila begins during oogenesis through the graded activation of the EGF receptor (EGFR)-Ras-MAPK signaling pathway in the follicle cell layer of the egg chamber. EGFR signaling, which is higher in dorsal follicle cells, represses expression of the sulfotransferase-encoding gene pipe, thereby delimiting a ventral domain of Pipe activity that is critical for the subsequent induction of ventral embryonic fates. We have characterized the transcriptional circuit that links EGFR signaling to pipe repression: in dorsal follicle cells, the homeodomain transcription factor Mirror (Mirr), which is induced by EGFR signaling, directly represses pipe transcription, whereas in ventral follicle cells, the HMG-box protein Capicua (Cic) supports pipe expression by repressing mirr. Although Cic is under negative post-transcriptional regulation by Ras-MAPK signaling in different contexts, the relevance of this mechanism for the interpretation of the EGFR signal during DV pattern formation remains unclear. Here, we consider a model where EGFR-mediated downregulation of Cic modulates the spatial distribution of Mirr protein in lateral follicle cells, thereby contributing to define the position at which the pipe expression border is formed.
authors.affiliation: Institut de Biologia Molecular de Barcelona-CSIC, Parc Científic de Barcelona, Barcelona, Spain.
authors.forename: María José
authors.initials: MJ
authors.lastname: Andreu
authors.forename: Leiore
authors.initials: L
authors.lastname: Ajuria
authors.forename: Núria
authors.initials: N
authors.lastname: Samper
authors.forename: Esther
authors.initials: E
authors.lastname: González-Pérez
authors.forename: Sonsoles
authors.initials: S
authors.lastname: Campuzano
authors.forename: Sergio
authors.initials: S
authors.lastname: González-Crespo
authors.forename: Gerardo
authors.initials: G
authors.lastname: Jiménez
mesh_terms: D000818:Animals; D019521:Body Patterning / Q000235:genetics*; D015536:Down-Regulation; D004330:Drosophila / Q000166:cytology* / Q000235:genetics / Q000378:metabolism; D029721:Drosophila Proteins / Q000235:genetics* / Q000378:metabolism / Q000502:physiology*; D004625:Embryo, Nonmammalian / Q000166:cytology / Q000378:metabolism; D066246:ErbB Receptors / Q000502:physiology*; D018507:Gene Expression Regulation, Developmental; D024002:HMGB Proteins / Q000235:genetics* / Q000378:metabolism / Q000502:physiology; D008954:Models, Biological; D018010:Receptors, Invertebrate Peptide / Q000502:physiology*; D012097:Repressor Proteins / Q000235:genetics* / Q000378:metabolism / Q000502:physiology; D015398:Signal Transduction; D015238:Sulfotransferases / Q000235:genetics / Q000378:metabolism
chemical_list: D029721:Drosophila Proteins; D024002:HMGB Proteins; D018010:Receptors, Invertebrate Peptide; D012097:Repressor Proteins; C404284:cic protein, Drosophila; C066532:Egfr protein, Drosophila; D066246:ErbB Receptors; D015238:Sulfotransferases; C115847:pip protein, Drosophila