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.
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http://dx.doi.org/10.1016/j.devcel.2006.08.012 | DOI Listing |
G3 (Bethesda)
November 2022
Department of Biology, Indiana University, Bloomington, IN 47405, USA.
Drosophila rhabdomeric terminal photoreceptor differentiation is an extended process taking several days to complete. Following ommatidial patterning by the morphogenetic furrow, photoreceptors are sequentially recruited and specified, and terminal differentiation begins. Key events of terminal differentiation include the establishment of apical and basolateral domains, rhabdomere and stalk formation, inter-rhabdomeral space formation, and expression of phototransduction machinery.
View Article and Find Full Text PDFG3 (Bethesda)
December 2019
Department of Cell and Systems Biology, University of Toronto, Ontario M5S 3G5, Canada
photoreceptor cells are highly polarized epithelial cells. Their apical membrane is further subdivided into the stalk membrane and the light-sensing rhabdomere. The photo-pigment Rhodopsin1 (Rh1) localizes to the rhabdomere, whereas the apical determinant Crumbs (Crb) is enriched at the stalk membrane.
View Article and Find Full Text PDFPLoS Genet
November 2014
Program in Genes & Development, The University of Texas Graduate School of Biomedical Sciences, Houston, Texas, United States of America; Department of Molecular & Human Genetics, Baylor College of Medicine, Houston, Texas, United States of America; Program in Developmental Biology, Baylor College of Medicine, Houston, Texas, United States of America.
The protein O-glucosyltransferase Rumi/POGLUT1 regulates Drosophila Notch signaling by adding O-glucose residues to the Notch extracellular domain. Rumi has other predicted targets including Crumbs (Crb) and Eyes shut (Eys), both of which are involved in photoreceptor development. However, whether Rumi is required for the function of Crb and Eys remains unknown.
View Article and Find Full Text PDFPLoS Genet
September 2014
Department of Biology, Indiana University, Bloomington, Indiana, United States of America.
Multicellular tubes consist of polarized cells wrapped around a central lumen and are essential structures underlying many developmental and physiological functions. In Drosophila compound eyes, each ommatidium forms a luminal matrix, the inter-rhabdomeral space, to shape and separate the key phototransduction organelles, the rhabdomeres, for proper visual perception. In an enhancer screen to define mechanisms of retina lumen formation, we identified Actin5C as a key molecule.
View Article and Find Full Text PDFCell Rep
November 2013
Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Avenida da República, 2780-157 Oeiras, Portugal.
The unfolded protein response (UPR) is composed by homeostatic signaling pathways that are activated by excessive protein misfolding in the endoplasmic reticulum. Ire1 signaling is an important mediator of the UPR, leading to the activation of the transcription factor Xbp1. Here, we show that Drosophila Ire1 mutant photoreceptors have defects in the delivery of rhodopsin-1 to the rhabdomere and in the secretion of Spacemaker/Eyes Shut into the interrhabdomeral space.
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