gurken and the I Factor Retrotransposon RNAs Share Common Localization Signals and Machinery

Drosophila gurken mRNA is localized by dynein-mediated transport to a crescent near the oocyte nucleus, thus targeting the TGF-α signal and setting up the primary embryonic axes. Here, we show that gurken and the I factor, a non-LTR retro-transposon, share a small consensus RNA stem loop of defined secondary structure, which forms a conserved signal for dynein mediated RNA transport to the oocyte nucleus. gurken and the I factor compete for the same localization machinery. We show that I factor transposition leads to its mRNA accumulating near and within the oocyte nucleus and causes perturbations in gurken and bicoid mRNA localization and axis specification. These observations further our understanding of the close association of transposable elements with their host, and provide an explanation for how I factor transposition causes female sterility. We propose that other transposable elements may exploit the host’s signals and machinery for RNA transport for their transposition.