The Department of Biomedicine

BBB seminar: Daniel St Johnston

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The localisation of oskar and bicoid mRNAs to opposite poles of the Drosophila oocyte

Daniel St Johnston
The Gurdon Institute, University of Cambridge, UK

mRNA localisation is a common mechanism for targeting proteins to the subcellular regions where they are required. One particularly striking example is the Drosophila oocyte, where the localisation of bicoid, oskar and gurken mRNAs to three distinct positions within this very large cell defines the anterior-posterior and dorsal-ventral axes of the embryo. Through a combination of genetic and biochemical approaches, we have identified a number of proteins that are required for the posterior localisation of oskar mRNA. Our results suggest that the oskar mRNA transport complex assembles in a stepwise manner as the mRNA moves from its site of transcription through the nucleus into the cytoplasm, and that multiple RNA-binding proteins are necessary to couple the mRNA to the localisation machinery.

Host: Anni Vedeler, Department of Biomedicine

Prof. Daniel St Johnston is a Wellcome Principal Research Fellow and a Member of the European Molecular Biology Organisation (EMBO). During the last 15 years he has focused on studying the molecular mechanisms underlying the origin of anterior-posterior polarity and mRNA localisation in the Drosophila embryo. These studies have led to many important new discoveries for which he has been awarded the EMBO Gold Medal

Recent publications:
St Johnston D (2005) Moving messages: the intracellular localization of mRNAs. Nat Rev Mol Cell Biol. [ahead of print]
Cinnamon E, Gur-Wahnon D, Helman A, St Johnston D, Jimenez G, Paroush Z (2004) Capicua integrates input from two maternal systems in Drosophila terminal patterning. EMBO J 23, 4571-4582
Huynh JR, St Johnston D (2004) The origin of asymmetry: early polarisation of the Drosophila germline cyst and oocyte. Curr Biol 14, R438-49
Huynh JR, Munro T, Smith Litière K and St Johnston D (2004) The Drosophila hnRNPA/B homologue, Hrp48, is specifically required for a distinct step in osk mRNA localisation. Dev Cell 6, 625-635
Palacios I, Gatfield D, St Johnston D and Izaurralde I (2004) An eIF4AIII-containing complex required for mRNA localization and nonsense-mediated mRNA decay. Nature 427, 753-757
Ephrussi A, St Johnston D (2004) Seeing is believing: the bicoid morphogen gradient matures. Cell 116, 143-152