Primordial germ cell migration in Drosophila melanogaster is controlled by somatic tissue

Abstract

In Drosophila, as in many other organisms, primordial germ cells show invasive and migratory behavior moving from their site of origin to the somatic component of the gonad. At a characteristic time in development, the primordial germ cells pass across the primordium of the gut and migrate on its outer surface toward the mesoderm, where they eventually associate with the somatic tissues of the gonad. Here we demonstrate that the exit and migration are specific behaviors of the primordial germ cells and that they are controlled by the somatic tissue of the embryo rather than by a germ cell autonomous clock. Using mutations, we show that these controlling somatic events probably occur in the tissue of the gut primordium itself.

Characterization of the Role of <i>aeneas</i> in Primordial Germ Cell Migration and Blastoderm Cellularization

“…and huckebein (hkb) mutants. In these mutants, the PMG epithelium is misdetermined to become hindgut epithelium (Reuter, 1994;Warrior, 1994;Jaglarz and Howard, 1994;Brönner and Jäckle, 1996;. A similar PGC migration phenotype has been shown for mutants of the G-Protein coupled receptor Trapped in endoderm 1 (Tre1) (Kunwar et al, 2003).…”

“…They intercalate the epithelial cells of the PMG pocket and transmigrate the epithelium. Several studies have shown that this process is not exclusively mediated by the PGCs but that it also requires changes in the epithelial cells of the PMG (Jaglarz and Howard 1994;Callaini et al, 1995;Warrior, 1994).…”

“…During PGC transmigration, the PMG epithelium undergoes morphological changes, which can be observed also in the absence of PGCs (Jaglarz and Howard 1994;Callaini et al, 1995). The epithelial cells of the PMG form pseudopodia on their luminal surface, contacting the PGCs.…”

“…The epithelial cells of the PMG form pseudopodia on their luminal surface, contacting the PGCs. Upon contact with the PGCs, discontinuities in the adhesive belts of neighboring PMG cells occur, permitting the transit of the PGCs (Jaglarz and Howard, 1994). The PMG epithelium therefore appears to possess specialized traits that actively promote the process of transmigration.…”

“…An experimental alternative would be the transplantation of wt PGCs on aen mutant embryos. In this experiment, PGCs are extracted from fluorescein labelled donor embryos of stage 3-4 and injected into the periembryonic space at the posterior pole of a recipient embryo (Jaglarz and Howard, 1994). This technique has been utilized to investigate PGC migratory behaviour during stage 10 (Jaglarz and Howard, 1994;Howard, 1995, Kunwar et al, 2003), however several problems make this solution inapplicable for the investigation of the aen phenotype.…”