Drosophila retinal morphogenesis during pupation and the role of integrins in retinal development
Abstract
The research presented characterizes in detail for the first time the cell movements and shape changes that take place during the pupal stage of Drosophila retinal morphogenesis. In order to establish the adult topology, a coordinated set of cone cell and photoreceptor movements eclipses the apical surfaces of the photoreceptors from the epithelium's apical surface, rotates the surfaces by 90$\sp\circ$, and then anchors them to the basal feet of the cone cells. Coincident with these movements is the construction of the photosensitive element, the rhabdomere, at the apical surfaces of the photoreceptors. In addition, a specialized retinal floor, called the fenestrated membrane, is created during pupation. Anchorage of the cone cell-photoreceptor complex to this floor is necessary for proper elongation of apical surfaces during the last half of pupation. Genetic analysis of integrins, the family of extracellular matrix receptors, shows they are essential for the anchorage of cells to the fenestrated membrane. Mutants containing a hypomorphic allele of the common b subunit (mys$\sp{nj42}$) display disruptions of the floor structures, including detachment of both the photoreceptor-cone cell complex and the basal feet of the secondary and tertiary pigment cells from the floor. Also, the distributions of three actin-binding proteins, nonmuscle myosin, $\alpha$-actinin, and spectrin, during pupation suggests that a transient cytoskeletal network may be constructed to support the initial phases of rhabdomere formation.
Degree
Ph.D.
Advisors
Ready, Purdue University.
Subject Area
Molecular biology
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