The control of polarity in eggs and epithelia. (360G-Wellcome-080007_B_06_Z)

The anterior-posterior axis of Drosophila is determined by the localisation of bicoid and oskar mRNAs to opposite poles of the oocyte, and provides an excellent system to investigate the conserved mechanisms of cell polarity and mRNA localisation. 1) We plan to screen the whole genome for mutants that affect the localisation of fluorescently-labelled bicoid and oskar mRNAs in living oocytes, in order to identify genes required for oocyte polarity and the localisation of each mRNA 2) The recruitment of the PAR-1 kinase to the oocyte posterior is the first sign of anterior-posterior polarity. We will characterise a number of genes required for this localisation, and use a proteomics approach to identify proteins that interact with PAR-1 in vivo. 3) Since PAR-1 regulates the organisation of the microtubule cytoskeleton, we will perform biochemical screens for PAR-1 substrates that associate with microtubules, and analyse several candidate proteins identified by genetic screens and bioinformatics. 4) We will characterise the components of the oskar mRNA and bicoid mRNA localisation complexes using genetic and proteomics approaches, and will visualise their localisation in vivo. 6) We will develop an oskar mRNA in vitro motility assay to determine how the motors that move it are regulated.