The development of the Drosophila embryonic gonad requires the migration of primordial germ cells (PGCs) towards somatic gonadal precursors (SGPs). Previous studies have implicated a role for the ATP-binding cassette (ABC) transporter Mdr49 during this event, suggesting that it functions in the export of a PGC attractant. Here, Girish Deshpande and co-workers further explore the function of Mdr49 in flies (p. ). They report that Mdr49 mutant embryos exhibit PGC migration defects but that these can be alleviated by a cholesterol-rich diet. Given that cholesterol is known to be involved in Hedgehog (Hh) precursor protein processing, the authors explore the potential link between Hh signalling and PGC migration. Their studies demonstrate genetic interactions between Mdr49 and genes encoding Hh pathway components, both during PGC migration and wing development. Importantly, the authors reveal that Hh release from hh-expressing cells is compromised in Mdr49 mutant embryos. Overall, these findings highlight a role for Mdr49 in the Hh pathway and lead the authors to propose that Mdr49 functions to allow SGPs to produce sufficient amounts of processed Hh that, in turn, signals to guide migrating PGCs.
