The role of actin regulators in polarity and membrane organisation of epithelial like cells in early Drosophila embryogenesis

Abstract

The syncytial Drosophila embryo has an epithelial like plasma membrane (PM) with an apical like and lateral like membrane domains even in the absence of complete cells. Previous studies in lab showed polarised distribution of plasma membrane proteins like Bazooka, Peanut and Patj and the hexagon dominant membrane packing of epithelial like cells in Drosophila early embryogenesis. We are studying the role of the actin cytoskeleton in maintaining plasma membrane polarity and polygonal packing in Drosophila early syncytial and cellularisation stages. RNAi mediated knockdown, OvoD1 germline clone strategy and pharmacological inhibitors are used to generate embryo mutants for branched and bundled actin regulators such as Arp2/3, WASP and Rhogef2 and Diaphanous respectively. Our studies show that Bazooka and Peanut are delocalised in the XY plane of the plasma membrane of RNAi mediated knockdown of bundled actin mutant embryos. Patj distribution remains largely unaffected and reveals morphogenetic defects in branched and bundled actin mutant embryos. Polygon analysis showed a shift towards greater numbers of pentagons in branched and bundled actin mutant embryos. Short metaphase furrow canals and loose membrane are seen during syncytial stages for embryos mutant for RhoGEF2 RNAi. We are able to show actin cytoskeleton possibly plays an important role in the localisation of Bazooka during early syncytial stages and maintains polygonal organisation of epithelial cells in early Drosophila embryogenesis.