title: Pattern formation by a moving morphogen source.
abstract: During Drosophila melanogaster oogenesis, the follicular epithelium that envelops the germline cyst gives rise to an elaborate eggshell, which houses the future embryo and mediates its interaction with the environment. A prominent feature of the eggshell is a pair of dorsal appendages, which are needed for embryo respiration. Morphogenesis of this structure depends on broad, a zinc-finger transcription factor, regulated by the EGFR pathway. While much has been learned about the mechanisms of broad regulation by EGFR, current understanding of processes that shape the spatial pattern of broad expression is incomplete. We propose that this pattern is defined by two different phases of EGFR activation: an early, posterior-to-anterior gradient of EGFR signaling sets the posterior boundary of broad expression, while the anterior boundary is set by a later phase of EGFR signaling, distributed in a dorsoventral gradient. This model can explain the wild-type pattern of broad in D. melanogaster, predicts how this pattern responds to genetic perturbations, and provides insight into the mechanisms driving diversification of eggshell patterning. The proposed model of the broad expression pattern can be used as a starting point for the quantitative analysis of a large number of gene expression patterns in Drosophila oogenesis.
authors.affiliation: Department of Chemical and Biological Engineering, Lewis Sigler Institute for Integrative Genomics, Carl Icahn Laboratory, Washington Road, Princeton University, Princeton, NJ 08544, USA. jzartman@nd.edu
authors.forename: Jeremiah J
authors.initials: JJ
authors.lastname: Zartman
authors.forename: Lily S
authors.initials: LS
authors.lastname: Cheung
authors.forename: Matthew G
authors.initials: MG
authors.lastname: Niepielko
authors.forename: Christine
authors.initials: C
authors.lastname: Bonini
authors.forename: Benjamin
authors.initials: B
authors.lastname: Haley
authors.forename: Nir
authors.initials: N
authors.lastname: Yakoby
authors.forename: Stanislav Y
authors.initials: SY
authors.lastname: Shvartsman
mesh_terms: D000465:Algorithms; D000818:Animals; D019521:Body Patterning; D029721:Drosophila Proteins / Q000235:genetics / Q000378:metabolism*; D004331:Drosophila melanogaster / Q000196:embryology* / Q000235:genetics / Q000378:metabolism; D066246:ErbB Receptors / Q000235:genetics / Q000378:metabolism*; D018507:Gene Expression Regulation, Developmental; D008954:Models, Biological; D015398:Signal Transduction; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism; D016335:Zinc Fingers
chemical_list: C102117:Br protein, Drosophila; D029721:Drosophila Proteins; D014157:Transcription Factors; D066246:ErbB Receptors