Spatially restricted activity of a Drosophila lipid phosphatase guides migrating germ cells.

Temporal and spatial controls of cell migration are crucial during normal development and in disease. Our understanding, though, of the mechanisms that guide cells along a specific migratory path remains largely unclear. We have identified wunen 2 as a repellant for migrating primordial germ cells. We show that wunen 2 maps next to and acts redundantly with the previously characterized gene wunen, and that known wunen mutants affect both transcripts. Both genes encode Drosophila homologs of mammalian phosphatidic acid phosphatase. Our work demonstrates that the catalytic residues of Wunen 2 are necessary for its repellant effect and that it can affect germ cell survival. We propose that spatially restricted phospholipid hydrolysis creates a gradient of signal necessary and specific for the migration and survival of germ cells.