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BP: Fachverband Biologische Physik

BP 16: Poster Session I

BP 16.22: Poster

Dienstag, 27. März 2007, 17:00–19:30, Poster D

Intranuclear dynamics of single mRNA molecules in living C. tentans salivary gland cell nuclei — •Roman Veith, Jan-Peter Siebrasse, and Ulrich Kubitscheck — Institute of Physical and Theoretical Chemistry, Bonn, Germany

The salivary glands of the dipteran Chironomus tentans provide an elegant model system for the analysis of specific messenger ribonucleoprotein particles, the Balbiani Ring (BR) mRNPs. BR mRNPs contain long RNA transcripts of roughly 35-40 kb in size, which possess a highly repetitive sequence. The diameter of the granular BR mRNPs is about 50 nm. Transcription and splicing of the BR mRNA and the formation of the BR particles was genetically and biochemically thoroughly investigated, and in several recent studies their intranuclear localisation in fixed glands was visualized by electron microscopy. However, up to now little was known about the intranuclear dynamics and mobility of the BR mRNPs. We analysed the intranuclear motions of BR particles in real-time by single particle tracking of fluorescence labelled BR mRNPs in living cell nuclei. Labelling was achieved in situ by nuclear microinjection of Cy5-conjugated oligonucleotides, which were complementary to the highly repetitive sequence on the BR mRNA. This approach generated fluorescent RNPs in vivo. Injection of control oligos and application of DRB proved that the labelling was specific. Using high speed single-molecule microscopy we analysed the intranuclear movements of the particles, and compared it to various model particles such as fluorescent microbeads, quantum dots and fluorescent dextrans.