The appoach of Golgi proteins and heparan sulfate proteoglycans (HSPGs) in the regulation of morphogen distribution in Drosophila
Date Issued
2005
Date
2005
Author(s)
Chen, Chung-Hao
DOI
en-US
Abstract
Morphogens are signaling proteins which form their own specific gradients over the developing tissues and subsequently pattern the field by activating different sets of genes at distinct signaling intensities. In recent years, macromolecules heparan sulfate proteoglycans (HSPGs) which locate on the cell surface were found to be essential for modulating the movement and distribution of multiple morphogens such as Hedgehog (Hh), Wingless (Wg) and Decapentaplegics (Dpp) in Drosophila wing imaginal discs. In previous studies, we identified a novel segment polarity gene, rotini (rti), which determines the distribution of these essential morphogens and is required for the normal expression of functional HSPGs. Additionally, we found Rti is a Golgi-resided protein and capable to physically interact with a putative V-SNARE, dVti1, that is a core member in the process of vesicle traffickings. Therefore, we suggest that Rti is a novel component in the trafficking pathway and the Rti-mediated transportation is necessary for the biosynthesis of functional HSPGs, which in turn influences the HSPGs-controlled morphogen behaviors on the cell surface.
Moreover, we found one glypican of HSPGs core proteins, Dally-like (Dlp), is almost absent within cells along the D-V boundary of wing discs, and this pattern is roughly complementary to Wg expression. Our analysis showed that high level of Wg signaling is not only necessary but also sufficient to repress Dlp expression in the wing pouch and notum region in wing discs. As the Dlp-composed HSPGs are potent to modulate Wg distribution, we suggest that Wg can restrict its own spreading range via its own signaling. It also indicates that the regulations on HSPGs and morphogens are interdependent.
Subjects
多醣蛋白
形態決定素
Golgi
HSPGs
morphogen
Type
other
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