title: closca, a new gene required for both Torso RTK activation and vitelline membrane integrity. Germline proteins contribute to Drosophila eggshell composition.
abstract: The Drosophila eggshell is a specialised extracellular matrix (ECM) that surrounds and protects the oocyte and the embryo until its eclosion. In addition, the vitelline membrane, the innermost layer of the eggshell, holds the local determinant required to activate the Torso RTK pathway, which establishes the embryonic terminal regions. Here we report the identification and characterisation of closca, a gene encoding a new member of a group of proteins that act non-redundantly in vitelline membrane biogenesis and in Torso signalling. We also show that the Nasrat protein, another member of this group, is incorporated into the vitelline membrane, thereby indicating that the eggshell is a shared ECM that receives contributions from both follicle cells and the germline. This observation also provides a new scenario that accounts for the long known contribution of germline products to vitelline membrane biogenesis and to the follicle cell-dependent activation of the Torso receptor.
authors.affiliation: Institut de Biologia Molecular de Barcelona (CSIC) and Institut de Recerca de Biomèdica, Barcelona, Spain.
authors.forename: Gemma
authors.initials: G
authors.lastname: Ventura
authors.forename: Marc
authors.initials: M
authors.lastname: Furriols
authors.forename: Nicolás
authors.initials: N
authors.lastname: Martín
authors.forename: Vitor
authors.initials: V
authors.lastname: Barbosa
authors.forename: Jordi
authors.initials: J
authors.lastname: Casanova
mesh_terms: D000483:Alleles; D000818:Animals; D029721:Drosophila Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D004331:Drosophila melanogaster / Q000196:embryology*; D005109:Extracellular Matrix / Q000378:metabolism; D005260:Female; D018507:Gene Expression Regulation, Developmental; D005854:Germ Cells; D008565:Membrane Proteins / Q000378:metabolism; D008954:Models, Biological; D009154:Mutation; D011505:Protein-Tyrosine Kinases / Q000378:metabolism; D019908:Proto-Oncogene Proteins c-raf; D020794:Receptor Protein-Tyrosine Kinases / Q000378:metabolism; D017422:Sequence Analysis, DNA; D014817:Vitelline Membrane / Q000196:embryology* / Q000378:metabolism
chemical_list: D029721:Drosophila Proteins; D008565:Membrane Proteins; C551351:clos protein, Drosophila; C454059:fs(1)N protein, Drosophila; D011505:Protein-Tyrosine Kinases; D020794:Receptor Protein-Tyrosine Kinases; C080148:tor protein, Drosophila; D019908:Proto-Oncogene Proteins c-raf; C420924:Raf protein, Drosophila