DFG Research Group FOR855

    Functional Analysis of the Exon Junction Complex in RNA Surveillance

    Prof. Andreas E. Kulozik
    Dr. N. Gehring 

    Project Summary:

    During splicing in the nucleus of metazoan cells, the spliceosome deposits the exon junction complex (EJC) on the nascent mRNA. The EJC modulates important nuclear and cytoplasmic events in gene expression such as nuclear mRNA export, nonsense-mediated mRNA decay, polysome association and translation. Components of the EJC are also involved in the localization of specific transcripts during embryogenesis. We will analyze the composition, the protein-protein interactions, and the assembly hierarchy of the entire EJC in an in-vitro splicing system and will study the functional role of individual components in vivo. This project will thus address the mechanism of one of the key post-transcriptional machines in higher eukaryotes, which integrates nuclear and cytoplasmic steps of the gene expression pathway.

    Selected publications (2007-09):

    1) Viegas MH, Gehring NH, Breit S, Hentze MW, Kulozik AE. The abundance of RNPS1, a protein component of the exon junction complex, can determine the variability in efficiency of the Nonsense Mediated Decay pathway. Nucleic Acids Res. 2007;35(13):4542-51.

    2) Danckwardt S, Kaufmann I, Gentzel M, Foerstner KU, Gantzert AS, Gehring NH, Neu-Yilik G, Bork P, Keller W, Wilm M, Hentze MW, Kulozik AE. Splicing factors stimulate polyadenylation via USEs at non-canonical 3' end formation signals. EMBO J. 2007 Jun 6;26(11):2658-69.

    3) Ivanov PV, Gehring NH, Kunz JB, Hentze MW, Kulozik AE. Interactions between UPF1, eRFs, PABP and the exon junction complex suggest an integrated model for mammalian NMD pathways. EMBO J. 2008 Mar 5;27(5):736-47.

    4) Gehring NH, Hentze MW, Kulozik AE. Tethering assays to investigate nonsense-mediated mRNA decay activating proteins. Methods Enzymol. 2008;448:467-82.

    5) Gehring NH, Lamprinaki S, Kulozik AE, Hentze MW. Disassembly of exon junction complexes by PYM. Cell. 2009 May 1;137(3):536-48. PubMed PMID: 19410547.

    6) Clerici M, Mourão A, Gutsche I, Gehring NH, Hentze MW, Kulozik A, Kadlec J, Sattler M, Cusack S. Unusual bipartite mode of interaction between the nonsense-mediated decay factors, UPF1 and UPF2. EMBO J. 2009 Jun 25;28(15):2293-2306.

    7) Gehring NH, Lamprinaki S, Hentze MW, Kulozik AE. The hierarchy of exon-junction complex assembly by the spliceosome explains key features of mammalian nonsense-mediated mRNA decay. PLoS Biol. 2009 May 26;7(5):e1000120.