However, rRNA gene expression has been demonstrated at this time. This issue was addressed by localizing the potent transcriptional activator Gal4-VP16 to the germline. Localization of germ plasm to the anterior reveals that it is sufficient to repress Bicoid-dependent gene expression. Thus, even in the presence of known transcriptional activators, RNAP II dependent gene expression is actively repressed in early germ cells. This expression is very soon after the time that germ cells become competent for expression of RNAP II target genes, as judged by experiments with Gal4-VP16.
Vasa protein is found in ovaries from the late third-instar larvae in precursors of oogonia.
It begins to be transported to the oocyte during stage ten, where it is first found in the perinuclear nuage, the same location as early Gurken protein. Vasa protein soon accumulates at the posterior pole of the oocyte. The Vasa transcript is not localized. After fertilization and the completion of mitotic cycle 9, Vasa protein accumultes in the pole cells. The posterior group of maternal genes is required for the development of the abdominal region in the Drosophila embryo.