Fly stocks used in this work.

Stocks of flies segregating the hau9G14 and both gho mutations were obtained from the Tübingen Stock Collection (http://www.eb.tuebingen.mpg.de/departments/3-genetics/drosophila/drosophila-stock-collection/drosophila-stock-collection). The hauCK segregating flies were generated by Kay Giesen in the laboratory of Christian Klämbt (Münster University). The sar1 stock was a kind gift of Christos Samakovlis (Stockholm University). Flies that segregate deficiencies in the hau or gho chromosomic region were obtained from the Bloomington Stock Center (Indiana University, Bloomington, USA). All mutant stocks were kept over respective balancers carrying Kr-Gal4 and UAS-GFP [26].