Prof. Denis LJ LAFONTAINE, ULB-FRS/FNRS
Denis.Lafontaine@ulb.ac.be
Denis L.J. LAFONTAINE obtained a BSc (1991) and a PhD (1995) in Molecular Biology & Genetics from the University of Namur (Belgium). He performed a post-doctoral training with Prof David Tollervey in the Gene Expression programme (EMBL, Heidelberg) and The Welcome Trust Center for Cell Biology (University of Edinburgh). Denis is Maître de Recherche of the Belgian FNRS and leads a group studying RNA metabolism at the Institute of Molecular Biology & Medecine at the University of Brussels since 2001. Denis is working on several aspects of RNA metabolism (including, surveillance and quality controls, pre-rRNA synthesis, processing & modification, pre-ribosome assembly & trafficking) and organelle morphogenesis (nucleolus and cytoplamsic P-bodies) with a particular focus on their relationships to human diseases (cancer). Denis published >30 manuscripts in international peer-reviewed journals and contributed chapters to several books destined to specific and general audiences. Denis is acting as a referee for top journals in the field of Molecular and Cellular Biology, as well as for international funding agencies. In 2012, Denis was nominated as an Academic Editor and joined the editorial board of PLoS ONE
Emilien Nicolas, Ph. D.
emilien.nicolas@ulb.ac.be
Emilien Nicolas obtained a master degree in Biology (2006) and a PhD (2011) at the ‘Université Catholique de Louvain’ (UCL) in the lab of Prof Bernard Hallet. He conducted a postdoctoral training at the University of Oxford at the Biochemistry Department under the supervision of Prof David J. Sherratt (2011-2012). During his training, Emilien acquired a strong expertise in molecular biology and genetics of prokaryotes (mainly E. coli). He was particularly interested in understanding how the molecular machinery acting on genes perform their function at the molecular (biochemistry) and cellular (genetics, live cell imaging) levels. During his work, Emilien developed an expertise in several microscopy techniques, including: wide field, confocal, PALM and OMX technologies. Emilien is currently working in the lab of Prof Denis L.J. Lafontaine on different aspects of the structure-function relationships within the nucleolus, a disease-related organelle essential for gene expression where ribosome synthesis is initiated.
Automation and quantitative morphometry
Equipment
- The BD Pathway ‘high content analysis system’ 435 (BD, U.S.A.)
- Plate-forme multimodale à haute résolution pour morphométrie quantitative
Bibliographical references
1. Servienė E, Lukša J, Orentaitė I, Lafontaine DLJ, Urbonavičius J (2012) Screening the Budding Yeast Genome Reveals Unique Factors Affecting K2 Toxin Susceptibility. PLoS ONE 7: e50779
2. Figaro S, Wacheul L, Schillewaert S, Graille M, Huvelle E, Mongeard R, Zorbas C, Lafontaine DLJ, Heurgué-Hamard V (2012) Trm112 is required for Bud23-mediated methylation of the 18S rRNA at position G1575. Mol Cell Biol 32: 2254-2267.
3. Schillewaert S, Wacheul L, Lhomme F, Lafontaine DLJ (2012) The Evolutionarily Conserved Protein LAS1 Is Required for Pre-rRNA Processing at Both Ends of ITS2. Mol Cell Biol 32: 430-444.
4. Mullineux ST, Lafontaine DL (2012) Mapping the cleavage sites on mammalian pre-rRNAs: Where do we stand? Biochimie PMID: 22342225.
5. Thiry M, Lamaye F, Lafontaine DLJ (2011) The nucleolus: When two became three. Nucleus 2: 289-293.
6. Leporé L, Lafontaine DLJ (2011) A functional interface at the rDNA connects rRNA synthesis, pre-rRNA processing and nucleolar surveillance in budding yeast. PLoS ONE : e24962.
7. Lamaye F, Galliot S, Alibardi L, Lafontaine DLJ, Thiry M (2011) Nucleolar structure across evolution: the transition between bi- and tricompartmentalized nucleoli lies within the class Reptilia. J Struct Biol 174: 352-359.
8. Leporé N, Lafontaine DLJ (2010) {'Catch me if you can': how the structural and functional integrity of eukaryotic RNA molecules is monitored by surveillance mechanisms}. Médecine/Sciences 26: 259-266.
9. Lafontaine DLJ (2010) A ‘garbage can’ for ribosomes: how eukaryotes degrade their ribosomes? Trends Biochem Sci 35: 267-277.
10. Hernandez-Verdun D, Roussel P, Thiry M, Sirri V, Lafontaine DLJ (2010) The nucleolus: structure/function in RNA metabolism. Wiley Interdisciplinary Reviews: RNA 1: 415-431.
Applications
High throughput screening with visual readout
E.g.: siRNA-mediated screening in human cell lines for the alteration in the subcellular distribution of a protein of interest
E.g.: screening for morphological altérations at the cellular and subcellular levels
E.g.: screening for testing the effects of drugs in cellular différentiation protocoles
Description
In Cell Biology, it is quite common that within a population many cells show different phenotype, a phenomenon known as “penetrance” that has to be quantified by statistical approaches. By numerical characterization, quantitative morphometry statistically validates various objects such as the different cell types or particular sub-cellular structures (for example the organelles).
It includes counting objects, calculating their diameter, surface, volume, level of the co-localization of different antigens, etc. The recognition of the cellular and sub-cellular structures can either be done on the basis of their particular morphology (histochemistry) or their fluorescence signal (using protein or RNA reporters). As the segmentation of the images is highly dependent on the parameters chosen, a key aspect of our work is the exact determination of the parameters used by the imaging software for the autonomous recognition and discrimination of the objects of interest (see the illustration).
These automated analysis techniques (high-content analysis) allow to (i) determine the number of bacteria in the cytoplasm of macrophages, (ii) test the effects of dozens of synthetic molecules (“drug design”) on stem cell differentiation or (iii) on the sub-cellular localization pattern of antigens of interest (for ex. the dynamic re-localization of a membrane receptor in the cytoplasm).
Macroscopic applications such as lytic plaque analysis or the calculation of the relative distribution of several species of pathogenic organisms are possible. The development of working protocols is done in collaboration with the RNA metabolism laboratory of the Université Libre de Bruxelles.
See the poster: POSTER_CMMI_-_A.__Q._Morphometry.pdf
