The mechanism and role of apical wingless  mRNA localization in Drosophila.
Published: 2006
Language: eng
Number of pages: 165
ISBN-13: 9780494219331
Description: Many developing and adult tissues are composed of polarized epithelia. By high-resolution in situ hybridization, it is shown that the wingless mRNA transcript of the fruit fly  Drosophila melanogaster, which encodes a secreted Wnt growth factor, is apically localized in all epithelial tissues examined. This localization is mediated by three independently acting elements (WLEs) in the 3' untranslated region that differ from each other in their sequence, predicted secondary structure, rate of divergence within the Drosophila genus and mechanism of localization. All three are active in transgenic reporter constructs, but only WLE3 is localized when injected into living syncytial blastoderm embryos. Full WLE3 activity requires any one of several downstream accessory elements. WLE3 has a highly conserved stem-loop structure, with both the secondary structure and sequences within the double-stranded regions essential for activity. A comparison of WLE3 to other known localization elements in Drosophila reveals a potential cryptic motif for Dynein-mediated transport. The physiological importance of apical wingless mRNA localization was characterized by the replacement of these apical localization elements with uniformly- or basolaterally-localizing elements, which yields Wingless protein with altered intracellular and extracellular distributions and reduced signalling activities. Transcript localization represents a novel and conserved aspect of the wingless signalling pathway, which may prove to be a mechanism used commonly for elaborating epithelial cell polarity.
Notes: Source: Dissertation Abstracts International, Volume: 68-01, Section: B, page: 0087.

Thesis (Ph.D.)--University of Toronto, 2006.

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