title: The agrin/perlecan-related protein eyes shut is essential for epithelial lumen formation in the Drosophila retina.
abstract: The formation of epithelial lumina is a fundamental process in animal development. Each ommatidium of the Drosophila retina forms an epithelial lumen, the interrhabdomeral space, which has a critical function in vision as it optically isolates individual photoreceptor cells. Ommatidia containing an interrhabdomeral space have evolved from ancestral insect eyes that lack this lumen, as seen, for example, in bees. In a genetic screen, we identified eyes shut (eys) as a gene that is essential for the formation of matrix-filled interrhabdomeral space. Eys is closely related to the proteoglycans agrin and perlecan and secreted by photoreceptor cells into the interrhabdomeral space. The honeybee ortholog of eys is not expressed in photoreceptors, raising the possibility that recruitment of eys expression has made an important contribution to insect eye evolution. Our findings show that the secretion of a proteoglycan into the apical matrix is critical for the formation of epithelial lumina in the fly retina.
authors.affiliation: Department of Cell and Systems Biology, University of Toronto, Toronto, Ontario M5S 3G5, Canada.
authors.forename: Nicole
authors.initials: N
authors.lastname: Husain
authors.forename: Milena
authors.initials: M
authors.lastname: Pellikka
authors.forename: Henry
authors.initials: H
authors.lastname: Hong
authors.forename: Tsveta
authors.initials: T
authors.lastname: Klimentova
authors.forename: Kwang-Min
authors.initials: KM
authors.lastname: Choe
authors.forename: Thomas R
authors.initials: TR
authors.lastname: Clandinin
authors.forename: Ulrich
authors.initials: U
authors.lastname: Tepass
mesh_terms: D018171:Agrin / Q000502:physiology*; D000483:Alleles; D000595:Amino Acid Sequence; D000818:Animals; D004330:Drosophila / Q000196:embryology* / Q000235:genetics; D029721:Drosophila Proteins / Q000737:chemistry / Q000235:genetics / Q000502:physiology*; D004625:Embryo, Nonmammalian; D005136:Eye Proteins / Q000737:chemistry / Q000235:genetics / Q000502:physiology*; D017353:Gene Deletion; D019812:Heparan Sulfate Proteoglycans / Q000502:physiology*; D007150:Immunohistochemistry; D008954:Models, Biological; D008969:Molecular Sequence Data; D017434:Protein Structure, Tertiary; D012160:Retina / Q000166:cytology / Q000196:embryology* / Q000648:ultrastructure; D017386:Sequence Homology, Amino Acid
chemical_list: D018171:Agrin; D029721:Drosophila Proteins; D005136:Eye Proteins; D019812:Heparan Sulfate Proteoglycans; C514625:eys protein, Drosophila; C071927:perlecan