title: Border of Notch activity establishes a boundary between the two dorsal appendage tube cell types.
abstract: Boundaries establish and maintain separate populations of cells critical for organ formation. We show that Notch signaling establishes the boundary between two types of post-mitotic epithelial cells, the Rhomboid- and the Broad-positive cells. These cells will undergo morphogenetic movements to generate the two sides of a simple organ, the dorsal appendage tube of the Drosophila egg chamber. The boundary forms due to a difference in Notch levels in adjacent cells. The Notch expression pattern mimics the boundary; Notch levels are high in Rhomboid cells and low in Broad cells. Notch(-) mutant clones generate an ectopic boundary: ectopic Rhomboid cells arise in Notch(+) cells adjacent to the Notch(-) mutant cells but not further away from the clonal border. Pangolin, a component of the Wingless pathway, is required for Broad expression and for rhomboid repression. We further show that Broad represses rhomboid cell autonomously. Our data provide a foundation for understanding how a single row of Rhomboid cells arises adjacent to the Broad cells in the dorsal appendage primordia. Generating a boundary by the Notch pathway might constitute an evolutionarily conserved first step during organ formation in many tissues.
authors.affiliation: Department of Biochemistry, University of Washington, Box 357350, Seattle, WA 98195-7350, USA.
authors.forename: Ellen J
authors.initials: EJ
authors.lastname: Ward
authors.forename: Xiaofeng
authors.initials: X
authors.lastname: Zhou
authors.forename: Lynn M
authors.initials: LM
authors.lastname: Riddiford
authors.forename: Celeste A
authors.initials: CA
authors.lastname: Berg
authors.forename: Hannele
authors.initials: H
authors.lastname: Ruohola-Baker
mesh_terms: D000818:Animals; D019521:Body Patterning; D019070:Cell Lineage; D004330:Drosophila; D029721:Drosophila Proteins / Q000378:metabolism / Q000502:physiology; D018507:Gene Expression Regulation, Developmental; D008565:Membrane Proteins / Q000378:metabolism; D008938:Mitosis; D008954:Models, Biological; D011518:Proto-Oncogene Proteins / Q000502:physiology; D051880:Receptors, Notch / Q000378:metabolism / Q000502:physiology*; D015398:Signal Transduction; D014157:Transcription Factors / Q000378:metabolism; D014921:Wings, Animal / Q000196:embryology; D051155:Wnt1 Protein
chemical_list: C102117:Br protein, Drosophila; D029721:Drosophila Proteins; D008565:Membrane Proteins; D011518:Proto-Oncogene Proteins; D051880:Receptors, Notch; C081481:Rho protein, Drosophila; D014157:Transcription Factors; D051155:Wnt1 Protein; C074622:wg protein, Drosophila