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Bertrand Séraphin

Research Focus

Several of our lines of research revolve around splicing, its control and its consequences. Henceforth, we are analysing protein containing complexes and developing new tools for this purpose. These methods are generally useful for the analysis of cellular machines but proves particularly powerful to study both stable (snRNP, splicing factors) and dynamic (commitment complexes, pre-spliceosome, spliceosome) complexes containing proteins (and often also RNA) that are involved in intron excision.

We are particularly interested by the U1 snRNP that is involved in the early steps of intron recognition and by the recently discovered RES complex that also affects alternative splice site choice. Functional and structural characterisation of these assemblies is underway and benefits from interspecies comparisons between the human and yeast models.

We also analyse how nuclear RNA decay pathways, including the newly described process involving the Trf4/Air poly(A) polymerase, the Mtr4 helicase, and the exosome, may contribute to the production of alternative transcripts through the selective degradation of precursor, intermediates and/or products of the splicing reaction.

Finally, we also examine the structure/function of the EJC complex that may also contribute to the production of alternative transcripts through an effect on splicing and/or by contributing to the cytoplasmic degradation of specific messenger RNAs by the NMD pathway.

Publications

  1. Kuwasako, K., Dohmae, N., Inoue, M., Shirouzu, M., Taguchi, S., Güntert, P., Séraphin, B., Muto, Y. and Yokoyama, S. (2008). Complex assembly mechanism and an RNA-binding mode of the human p14-SF3b155 spliceosomal protein complex identified by NMR solution structure and functional analyses. Proteins 71(4), 1617-1636.
  2. Mauxion, F., Faux, C. and Séraphin, B. (2008). The BTG2 protein is a general activator of mRNA deadenylation. EMBO Journal 27(7), 1039-48.
  3. Le Hir, H. and Séraphin, B. (2008). EJCs at the heart of translational control. Cell 133(2), 213-6.
  4. Brooks, M., Dziembowski, A., Quevillon-Cheruel, S., Henriot, V., Faux, C., Van-Tilbeurgh, H., Séraphin, B. (2008). Structure of the yeast Pml1 splicing factor and its integration into the RES complex. Nucleic Acids Research  37(1), 129-43.
  5. Rougemaille, M., Gudipati, R. K., Olesen, J. R., Thomsen, R., Séraphin, B., Libri, D. and Jensen, T. (2007). Dissecting mechanisms of nuclear mRNA surveillance in THO/sub2 complex mutants. EMBO Journal 26(9), 2317-26.
  6. Buchet-Poyau, K., Courchet, J., Le Hir, H., Séraphin, B., Scoazec, J., Duret, L., Domon-Dell, C., Freund, J. and Billaud, M. (2007). Identification and characterization of human Mex-3 proteins, a novel family of evolutionarily conserved RNA-binding proteins differentially localized to processing bodies. Nucleic Acids Research 35(4), 1289-300.
  7. Dziembowski, A., Lorentzen, E., Conti, E., and Séraphin, B. (2007). A single subunit, Dis3, is essentially responsible for yeast exosome core activity. Nature Structural and Molecular Biology 14(1), 15-22.
  8. Lorentzen, E., Dziembowski, A., Lindner, D., Séraphin, B., and Conti, E. (2007). RNA channelling by the archaeal exosome. EMBO Reports 8(5), 470-6.
  9. Andersen, C.B., Ballut, L., Johansen, J.S., Chamieh, H., Nielsen, K.H., Oliveira, C.L., Pedersen, J.S., Séraphin, B., Le Hir, H., Andersen, G.R. (2006). Structure of the exon junction core complex with a trapped DEAD-box ATPase bound to RNA. Science 313, 1968-1972.
  10. Hernández, H., Dziembowski, A. Taverner, T., Séraphin, B., Robinson, C.V. (2006). Subunit architecture of multimeric complexes isolated directly from cells. EMBO Reports 7, 6, 605–610.
  11. Ballut, L., Marchadier, B., Baguet, A., Tomasetto, C., Séraphin, B., Le Hir, H. (2005). The exon junction core complex is locked onto RNA by inhibition of eIF4AIII ATPase activity. Nature Structural and Molecular Biology 12, 861-869.
  12. Wyers, F., Rougemaille, M., Badis, G., Rousselle, J.C., Dufour, M.E., Boulay, J., Regnault, B., Devaux, F., Namane, A., Séraphin, B., Libri, D., Jacquier, A. (2005). Cryptic pol II transcripts are degraded by a nuclear quality control pathway involving a new poly(A) polymerase. Cell 121, 725-737. 
  13. Séraphin, B., Pamblanco, M., Faux, C. and Dziembowski, A. (2005). The Tandem Affinity Purification (TAP) strategy for protein complex characterization. Cold Spring Harbor Laboratory Manual: Protein Interactions 2nd edition. Golermis, E. and Serebriiskii, I Editors. Cold Spring Harbor Laboratory Press (Cold Spring Harbor, NY) 761-774.
  14. Dziembowski, A., Ventura, A.-P., Rutz, B., Caspary, F., Faux, C., Halgand, F., Laprévote, O., Séraphin, B. (2004). Proteomic analysis identifies a new complex required for nuclear pre-mRNA retention and splicing. EMBO Journal 23, 4847-4856. 

Key lab techniques: commitment complexes, reporter gene, protein:protein interaction, protein-RNA interaction, protein complexes, RNA quality control, NMD, nuclear RNA decay, yeast Saccharomyces cerevisiae, mammalian cells, protein interaction methods, in vitro systems, recombinant factors.

Key lab reagents: tagged yeast strains, tagging constructs, expression clones.

Lab contact: Sandrine Patacchini: patacchini@cgm.cnrs-gif.fr

Lab website: www.cgm.cnrs-gif.fr/epissage/index.html