MRNA localization and ER-based protein sorting mechanisms dictate the use of transitional endoplasmic reticulum-golgi units involved in gurken transport in Drosophila oocytes.

ABSTRACT: The anteroposterior and dorsoventral axes of the future embryo are specified within Drosophila oocytes by localizing gurken mRNA, which targets the secreted Gurken transforming growth factor-alpha synthesis and transport to the same site. A key question is whether gurken mRNA is targeted to a specialized exocytic pathway to achieve the polar deposition of the protein. Here, we show, by (immuno)electron microscopy that the exocytic pathway in stage 9-10 Drosophila oocytes comprises a thousand evenly distributed transitional endoplasmic reticulum (tER)-Golgi units. Using Drosophila mutants, we show that it is the localization of gurken mRNA coupled to efficient sorting of Gurken out of the ER that determines which of the numerous equivalent tER-Golgi units are used for the protein transport

SUBMITTER: Herpers B 

PROVIDER: S-EPMC532012 | biostudies-literature | 2004 Dec

REPOSITORIES: biostudies-literature