Restoration of fertility in sterilized Drosophila eggs by transplantation of polar cytoplasm

Tudor and its domains: germ cell formation from a Tudor perspective

“…Similarly, later experiments in Drosophila showed that UV-irradiation of the germ plasm produces adult flies that lack germ cells [3]. However, when germ plasm from non-UV-irradiated embryos was transplanted into UV-irradiated embryos, germ cell formation was rescued [4]. Interestingly, the production of germ cells can be induced if germ plasm is injected into embryos at ectopic sites [5].…”

Valois, a component of the nuage and pole plasm, is involved in assembly of these structures, and binds to Tudor and the methyltransferase Capsuléen

“…Functional and structural characteristics of the germ plasm confer specific properties to this region of the egg. First, transplantation of posterior plasm from oocytes or early cleavage embryos induces ectopic formation of pole cells within the recipient embryos (Illmensee and Mahowald, 1974;Okada et al, 1974). Second, the pole plasm is devoid of yolk particles, but exhibits electrondense, ribonucleoprotein-rich organelles without delimiting membranes, called polar granules (Huettner, 1923;Mahowald, 1962;Illmensee et al, 1976).…”

Histological Differentiation of Primordial Germ Cells in Zebrafish

“…In worms, flies and frogs, a special cytoplasm called germ plasm or pole plasm (in flies) is located asymmetrically within eggs and is inherited into some cells, which differentiate into germ cells (Nieuwkoop and Sutasurya, 1979). The cytoplasm is believed to predetermine the fate of germ cell differentiation, because transplantation and UV irradiation experiments have led to perturbation of germ-cell formation in Drosophila (Okada et al, 1974;Illemensee and Mahowald, 1974;Kobayashi and Okada, 1989) and in anurans (Smith, 1966;Ikenishi et al, 1986). The cytoplasm contains specific RNA and protein, such as vasa (Hay et al, 1988;Bardsley et al, 1993;Komiya et al, 1994;Ikenishi et al, 1996;Ikenishi and Tanaka, 1997).…”