Studies of pattern formation and cell fate determination in the Drosophila compound eye: The role of therugose gene.
Item
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Title
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Studies of pattern formation and cell fate determination in the Drosophila compound eye: The role of therugose gene.
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Identifier
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AAI9707151
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identifier
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9707151
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Creator
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Shamloula, Hoda Kamal.
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Contributor
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Adviser: Tadmiri Venkatesh
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Date
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1996
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Language
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English
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Publisher
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City University of New York.
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Subject
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Biology, Genetics | Biology, Molecular | Biology, Neuroscience
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Abstract
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Understanding how complex and highly organized cellular patterns are formed is a fundamental question in developmental biology. The Drosophila compound eye is a highly precise cellular pattern readily amenable to genetic analysis. During the development of the Drosophila compound eye, cell-cell interactions play a critical role in the sequential determination of cell fates leading to a precise cellular patterns. The Drosophila compound eye consists of eight hundred unit-eye called ommatidia which are arranged in a regular symmetrical array. Each ommatidium is comprised of an invariant number of neural and nonneural cells arranged in a precise manner. The development of the retina begins with the differentiation of the neural photoreceptor cell R8 which orchestrates the differentiation of the other photoreceptors via inductive and inhibitory cues. Subsequently the nonneural cone and pigment cells are specified by unknown mechanisms. Cone cells and pigment cells are involved in the formation of the lens and the lattice between the ommatidia establishing specific cell-cell contacts needed for a functional retina. The cone cells, in addition to secreting the lens, are important in the formation of the retinal pattern and the fenestrated basement membrane that shapes and supports the entire retina. To study the cellular and molecular interactions that direct the retinal pattern formation, I have isolated and characterized mutations in the rugose gene. My genetic and phenotypic studies show that mutations at the rg locus (4E-F) results in a rough eye phenotype. Cobalt sulfide and electron microscope studies have shown that rg is required for proper differentiation of cone and pigment cells and for the formation of the fenestrated basement membrane. Genetic interaction studies show that rg may function in the EGF receptor mediated signal transduction pathway. The abnormal rg wing phenotype, that shows incomplete wing venation and multiple cross veins, supports the notion that rg may function through EGFr pathway. These results suggest that rg may be an important effector of the cone cell differentiation and its function may be mediated through the EGF receptor mediated signal cascade. A putative genomic DNA clone that encodes the rg gene has been isolated by chromosomal walking.
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Type
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dissertation
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Source
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PQT Legacy CUNY.xlsx
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degree
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Ph.D.
