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Laboratoire de Biologie Moléculaire Eucaryote

UMR 5099
Director: Pierre-Emmanuel Gleizes


The Laboratory of Eukaryotic Molecular Biology (LBME) is a joint CNRS-Université Paul Sabatier research unit that is part of the Center for Integrative Biology of Toulouse (CBI).


Research at LBME focuses on genetic and epigenetic mechanisms of genome expression, organization and maintenance in eukaryotes with emphasis on:

  • synthesis and functions of ribonucleoparticles, especially ribosome biogenesis and small non-coding RNAs
  • structural dynamics of chromatin and chromosomes


Our fundamental research projects contribute to the understanding of pathological disorders including rare diseases (Diamond-Blackman anemia and other ribosomopathies, Prader-Willi syndrome) and cancer.


The LBME manages high-end fluorescence and cryo-electron microscopy facilities that are part of the CBI technological platforms.

The Laboratoire de Biologie Moléculaire Eucaryote supports "Sciences en marche"






Senior Post-doc positions

News Archives

  • A new player of ribosome synthesis involved in dyskeratosis congenita

    Protein synthesis is performed by 5 to 10 millions of ribosomes in each human cell. These molecular machines are made of RNAs and proteins that are assembled following a complex and energy-consumming pathway. Defects in ribosome assembly are associated to various pathologies, including congenital diseases and cancers. A new study led Pierre-Emmanuel Gleizes and Marie-Françoise O’Donohue at LBME-CBI, in collaboration with the group of Ulrike Kutay at ETH-Zürich, now shows that PARN (Poly-A specific RiboNuclease), a 3’-5’ exonuclease mutated in dyskeratosis congenita and idiopathic pulmonary fibrosis, is an unexpected player of ribosome assembly. These new findings redefines PARN’s cellular function, which is mainly known for its role in mRNA turn-over, and enforce the hypothesis that a defect in ribosome synthesis could participate in the ethiology of dykeratosis congenita in some cases.

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  • A new 7SK-containing RNP regulates RNA pol II transcription in a gene-specific fashion

    The 7SK small nuclear RNP (snRNP), composed of the 7SK snRNA, Larp7 and MePCE, controls the transcriptional stimulatory function of the Positive Transcription Elongation Factor b (P-TEFb) through sequestering active P-TEFb into large transcriptionally inactive 7SK/P-TEFb RNP. The team of Tamás Kiss at LBME, in collaboration with the team of Shona Murphy (University of Oxford), identified a new 7SK complex encompassing the 7SK snRNP and the recently identified RNA pol II-specific spliceosomal snRNA transcription factor, the Little Elongation Complex (LEC). The 7SK/LEC RNP specifically associates with pol II-specific snRNA genes to promote RNA pol II recruitment and elongation. Depletion of 7SK snRNP disrupts LEC integrity, prevents LEC accumulation in Cajal bodies where 7SK/LEC assembly likely occurs and eventually, inhibits snRNA synthesis. Thus, 7SK is a multifunctional transcriptional regulatory snRNP that, besides controlling the global level of active P-TEFb, also functions as a classical gene-specific transcription factor that promotes expression of pol II-specific sn/snoRNA genes. This work has been published in the EMBO Journal.

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  • Functional link between Prp43 helicase activation and binding of the ATP base during eukaryotic ribosome biogenesis

    In eukaryotes, ribosome synthesis involves the assembly and maturation of large precursor particles, the pre-ribosomal particles, containing ribosomal RNA precursors, ribosomal proteins and numerous assembly and maturation factors. Among these factors, Prp43 belongs to the family of RNA helicases. Prp43 has the ability to hydrolyze ATP and modulate RNA-RNA interactions (helicase activity) and its function is controlled by protein co-factors containing so-called “G-patch domains”. In collaboration with Nicolas Leulliot (LCRB, Université Paris Descartes), we have identified Prp43 residues that interact directly with the base of the ATP molecule in the active site of the enzyme. A specific mutation abolishing this interaction inhibits the ATPase and helicase activities of Prp43 in vitro. This mutation induces defects in the maturation of the pre-ribosomal particles in yeast cells that are highly reminiscent of those induced by the inactivation of one of the G-patch co-factors of Prp43, the Gno1 protein. These data suggest that the pre-ribosomal particle maturation defects induced by this Prp43 mutation very likely result from an impaired activation of Prp43 by Gno1. This study reveals that the interaction between Prp43 residues and the ATP base are important for the activity and regulation of this family of helicases.


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  • G4 hunting season is open

    Guanine rich sequences (G) are able to adopt secondary structures called Guanine quadruplexes (G4). G4-forming sequences are associated with telomere biology, replication origins and regulation of gene expression but also with genetically instable sites. So far, the search of such sequences was based on pattern matches. Together with Jean-Louis Mergny (IECB , Bordeaux) , Laurent Lacroix of the Cuvier team from the LBME has developed a new predictive tool for G4 - G4Hunter - which led to re-evaluate by a factor of 2 to 10 the G4 propensity of many genomes.


  • Mating type specific folding of yeast chromosome III revealed by mathematical modelling of 3 color 3D live cell imaging

    How variations in the three-dimensional organization of chromosomes are regulated is key to gain better understanding of genome function from gene expression to DNA repair and recombination. In an article published in PLoS Computational Biology in June 2015, the Bystricky group in collaboration with Alain Kamgoué, Mathematics/Informatics at the LBME/LMGM, developed original quantitative image analysis methods to determine chromosome conformation from relative positions of multiple fluorescently tagged DNA loci.


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Laboratoire de Biologie
Moléculaire Eucaryote
UMR 5099