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Habilitation à diriger des recherches

Assemblage et fonction de complexes ARN-protéines

Abstract : Ribonucleoprotein particles (or RNPs) play essential roles in many fundamental cellular processes. Assembly of RNP particles is a complex process that requires several processing steps and multiple assembly factors. Proper formation of RNP particles is essential for their function. Thus, it is of fundamental importance to understand how RNPs are assembled within the cell. In my career I analyzed several aspects of these mechanisms.
During my thesis directed by Chantal Ehresmann (1990-1994) in the team of Bernard Ehresmann (UPR 9002 du CNRS), I studied the 16S rRNA binding site of E. coli ribosomal protein S8.
In the team of David Tollervey (EMBL, Heidelberg (1994-1996) and University d'Edinburg (1996-2001) I analyzed the mechanisms of maturation, assembly and degradation of various RNPs. I participated in the characterization of the exosome, a complex of 3'-5' exonucleases involved in the processing and degradation of various RNAs in yeast. I also studied the role of chaperone proteins in the biogenesis of snoRNAs (ribosome biogenesis), rRNAs and tRNAs.
In 2001 I was recruited by the CNRS in the team of Alain Krol to study the mechanisms of selenoprotein synthesis. Selenoprotein synthesis requires co-translational recoding of in-frame UGA codons. In eukaryotes, this process involves the assembly of RNA-protein complexes to specific stem-loops located in the 3'UTR of selenoprotein mRNAs, called Selenocysteine Insertion Sequences (SECIS). SECIS-binding protein 2 binds the SECIS element and recruits the factors of the biosynthesis machinery. SBP2 is part of supramolecular complexes and undergoes nucleocytoplasmic shuttling, indicating a possible nuclear assembly of the SECIS mRNP. The RNA-binding domain of SBP2 belongs to the L7Ae family of proteins. Members of this family are at the core of many RNPs and are thus involved in many cellular functions. L7Ae proteins are part of the large and small ribosomal sub-units (translation), box C/D and H/ACA snoRNPs (ribosomal RNA biogenesis), spliceosomal RNPs (splicing), telomerase (telomere replication), and selenoprotein mRNPs (translation of selenoproteins). Our aims are to elucidate the principles of SBP2/SECIS interaction, to identify the components of the complexes that bind to the SECIS and understand their assembly pathway.
In collaboration with Edouard Bertrand (Montpellier), Bruno Charpentier and Christiane Branlant (Nancy) we have identified a conserved molecular machinery for the assembly of RNPs of the L7Ae family. This machinery is conserved from yeast to human and of fundamental importance for the cell. It is composed of an adaptor protein and a complex of protein chaperones linked to HSP90. Our role is to understand it's specific role in selenoprotein mRNP formation.
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Habilitation à diriger des recherches
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https://tel.archives-ouvertes.fr/tel-00265610
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Submitted on : Wednesday, March 19, 2008 - 4:24:47 PM
Last modification on : Friday, November 27, 2020 - 11:16:02 AM
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  • HAL Id : tel-00265610, version 1

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Christine Allmang. Assemblage et fonction de complexes ARN-protéines. Sciences du Vivant [q-bio]. Université Louis Pasteur - Strasbourg I, 2007. ⟨tel-00265610⟩

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