title: The identification of novel genes required for Drosophila anteroposterior axis formation in a germline clone screen using GFP-Staufen.
abstract: The anteroposterior axis of Drosophila is defined during oogenesis, when the polarisation of the oocyte microtubule cytoskeleton directs the localisation of bicoid and oskar mRNAs to the anterior and posterior poles, respectively. Although maternal-effect lethal and female-sterile screens have identified many mutants that disrupt these processes, these screens could not recover mutations in essential genes. Here we describe a genetic screen in germline clones for mutants that disrupt the localisation of GFP-Staufen in living oocytes, which overcomes this limitation. As Staufen localises to the posterior with oskar mRNA and to the anterior with bicoid mRNA, it acts as a marker for both poles of the oocyte, allowing the identification of mutants that affect the localisation of either mRNA, as well as mutants that disrupt oocyte polarity. Using this approach, we have identified 23 novel complementation groups on chromosome 3R that disrupt anteroposterior axis formation. Analyses of new alleles of spn-E and orb show that both SPN-E and ORB proteins are required to organise the microtubule cytoskeleton at stage 9, and to prevent premature cytoplasmic streaming. Furthermore, yps mutants partially suppress the premature cytoplasmic streaming of orb mutants. As orb, yps and spn-E encode RNA-binding proteins, they may regulate the translation of unidentified RNAs necessary for the polarisation of the microtubule cytoskeleton.
authors.affiliation: The Wellcome Trust/Cancer Research UK Institute and the Department of Genetics, University of Cambridge, Tennis Court Rd, Cambridge CB2 1QR, UK.
authors.forename: Sophie G
authors.initials: SG
authors.lastname: Martin
authors.forename: Vincent
authors.initials: V
authors.lastname: Leclerc
authors.forename: Katie
authors.initials: K
authors.lastname: Smith-Litière
authors.forename: Daniel
authors.initials: D
authors.lastname: St Johnston
mesh_terms: D000818:Animals; D019521:Body Patterning / Q000235:genetics*; D003433:Crosses, Genetic; D004330:Drosophila / Q000196:embryology* / Q000235:genetics*; D029721:Drosophila Proteins / Q000235:genetics / Q000378:metabolism; D005260:Female; D017930:Genes, Reporter; D018398:Homeodomain Proteins / Q000235:genetics / Q000378:metabolism; D008297:Male; D009154:Mutation; D012333:RNA, Messenger; D015534:Trans-Activators / Q000235:genetics / Q000378:metabolism
chemical_list: D029721:Drosophila Proteins; D018398:Homeodomain Proteins; D012333:RNA, Messenger; D015534:Trans-Activators; C056478:bcd protein, Drosophila; C091675:osk protein, Drosophila