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General Comment |
Stephanie E. Mohr, et al 2001 reported that the RNA-binding protein Tsunagi interacts with
Mago Nashi to establish polarity and localize oskar
mRNA during Drosophila oogenesis.
In Drosophila melanogaster, formation of the axes and the primordial germ cells is regulated by interactions between
the germ line-derived oocyte and the surrounding somatic follicle cells. This reciprocal signaling results in the
asymmetric localization of mRNAs and proteins critical for these oogenic processes. Mago Nashi protein interprets the
posterior follicle cell-to-oocyte signal to establish the major axes and to determine the fate of the primordial germ
cells. In the yeast two-hybrid system , an RNA-binding protein, Tsunagi, interacts with Mago
Nashi protein. The proteins coimmunoprecipitate and colocalize, indicating that they form a complex in vivo.
Immunolocalization reveals that Tsunagi protein is localized within the posterior oocyte cytoplasm during stages 1-5
and 8-9, and that this localization is dependent on wild-type mago nashi function. When tsunagi function is removed
from the germ line, egg chambers develop in which the oocyte nucleus fails to migrate, oskar mRNA is not localized
within the posterior pole, and dorsal-ventral pattern abnormalities are observed. These results show that a Mago
Nashi-Tsunagi protein complex is required for interpreting the posterior follicle cell-to-oocyte signal to define the
major body axes and to localize components necessary for determination of the primordial germ cells.
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