A5063260712- RNA Research and Splicing
- Genomics and Chromatin Dynamics
- RNA and protein synthesis mechanisms
- RNA modifications and cancer
- Fungal and yeast genetics research
- Nuclear Structure and Function
- Genetics, Aging, and Longevity in Model Organisms
- Photosynthetic Processes and Mechanisms
- DNA Repair Mechanisms
- Advanced Electron Microscopy Techniques and Applications
- Cancer-related molecular mechanisms research
- Biofuel production and bioconversion
- Blood disorders and treatments
- Advanced Fluorescence Microscopy Techniques
- Molecular Biology Techniques and Applications
Université de Toulouse
2011-2025
Université Toulouse III - Paul Sabatier
2000-2024
Laboratoire de Biologie Moléculaire des Eucaryotes
1998-2020
Centre National de la Recherche Scientifique
1999-2019
Centre National pour la Recherche Scientifique et Technique (CNRST)
2011-2013
Ollscoil na Gaillimhe – University of Galway
2013
University of Regensburg
2010
Commissariat à l'Énergie Atomique et aux Énergies Alternatives
1999
CEA Paris-Saclay
1999
Approximately 25% of cases Diamond Blackfan anemia, a severe hypoplastic are linked to heterozygous mutations in the gene encoding ribosomal protein S19 that result haploinsufficiency for this protein. Here we show deletion either two genes Rps19 yeast severely affects production 40 S subunits. is an essential strictly required maturation 3′-end 18 rRNA. Depletion results accumulation aberrant pre-40 particles retained nucleus fail associate with pre-ribosomal factors involved late steps,...
RNA polymerase I (Pol I) produces large ribosomal RNAs (rRNAs). In this study, we show that the Rpa49 and Rpa34 Pol subunits, which do not have counterparts in II III complexes, are functionally conserved using heterospecific complementation of human Schizosaccharomyces pombe orthologues Saccharomyces cerevisiae. Deletion RPA49 leads to disappearance nucleolar structure, but assembly can be restored by decreasing gene copy number from 190 25. Statistical analysis Miller spreads absence...
Highlights•Single-cell monitoring shows that ERC accumulation starts well before senescence•ERC drives a large upregulation in pre-rRNA, but not ribosome, synthesis•A strong loss of nuclear homeostasis occurs downstream nucleolar defects•Rejuvenation daughters is ensured by asymmetrical partitioningSummaryBudding yeast cells undergo limited number divisions they enter senescence and die. Despite recent mechanistic advances, whether how molecular events are temporally causally linked during...
During the assembly process of ribosomal subunits, their structural components, RNAs (rRNAs) and proteins (r-proteins) have to join together in a highly dynamic defined manner enable efficient formation functional ribosomes. In this work, large subunit (LSU) r-proteins from eukaryote S. cerevisiae was systematically investigated. Groups LSU with specific characteristics were detected by comparing protein composition affinity purified early, middle, late or mature (precursor) particles...
Ribosome biogenesis is a major metabolic effort for growing cells. In Saccharomyces cerevisiae, Hmo1, an abundant high-mobility group box protein (HMGB) binds to the coding region of RNA polymerase I transcribed ribosomal RNAs genes and promoters ∼70% genes. this study, we have demonstrated functional conservation eukaryotic HMGB proteins involved in DNA (rDNA) transcription. We shown that when expressed budding yeast, human UBF1 newly identified Sp-Hmo1 (Schizosaccharomyces pombe) localize...
Ribosome biogenesis is tightly linked to cellular growth. A crucial step in the regulation of ribosomal RNA (rRNA) gene transcription formation complex between polymerase I (Pol I) and Pol I-dependent factor Rrn3p. We found that TOR inactivation leads proteasome-dependent degradation Rrn3p a strong reduction initiation competent I-Rrn3p complexes affecting yeast rRNA transcription. Using mutant expressing non-degradable or strain which defined endogenous levels can be adjusted by Tet-off...
Chromosomes architecture is viewed as a key component of gene regulation, but principles chromosomal folding remain elusive. Here we used high-throughput live cell microscopy to characterize the conformation and dynamics longest chromosome Saccharomyces cerevisiae (XII). Chromosome XII carries ribosomal DNA (rDNA) that defines nucleolus, major hallmark nuclear organization. We determined intranuclear positions 15 loci distributed every ∼100 kb along chromosome, investigated their motion over...
ABSTRACT How spatial organization of the genome depends on nuclear shape is unknown, mostly because accurate size and measurement technically challenging. In large cell populations yeast Saccharomyces cerevisiae, we assessed geometry (size shape) nuclei in three dimensions with a resolution 30 nm. We improved an automated fluorescence localization method by implementing post-acquisition correction spherical microscopic aberration along z-axis, to detect dimensional (3D) positions pore...
Abstract The RNA exosome is a multiprotein complex essential for maturation and degradation. In budding yeast, nine-subunit protein (Exo9) associated with Rrp44 forms Exo10 in the cytoplasm and, Rrp6, Exo11 nucleus. Depending on its subcellular localization, interacts different cofactors substrates. cytoplasm, associates SKI via Ski7, while nucleus, TRAMP complex. Within nucleolus, participates ribosomal (rRNA) processing, facilitated by Mtr4-dependent adaptors Utp18 Nop53. this manuscript,...
The RNA exosome is a multiprotein complex essential for maturation and degradation. In budding yeast, nine-subunit protein (Exo9) associated with Rrp44 forms Exo10 in the cytoplasm and, Rrp6, Exo11 nucleus. Depending on its subcellular localization, interacts different cofactors substrates. cytoplasm, associates SKI via Ski7, while nucleus, TRAMP complex. Within nucleolus, participates ribosomal (rRNA) processing, facilitated by Mtr4-dependent adaptors Utp18 Nop53. this manuscript, we have...
Abstract Intrinsically disordered regions (IDRs) are highly enriched in the nucleolar proteome but their physiological role ribosome assembly remains poorly understood. Our study reveals functional plasticity of extremely abundant lysine-rich IDRs small ribonucleoprotein particles (snoRNPs) from protists to mammalian cells. We show Saccharomyces cerevisiae that electrostatic properties this IDR, KKE/D domain, promote snoRNP accumulation vicinity nascent rRNAs, facilitating modification....
Using Saccharomyces cerevisiae strains with genetically modified nucleoli, we show here that changing parameters as critical the tandem organization of ribosomal genes and polymerase transcribing rDNA, although profoundly modifying position shape nucleolus, only partially alter its functional subcompartmentation. High-resolution morphology achieved by cryofixation, together ultrastructural localization nucleolar proteins rRNA, reveals structure, arising upon transcription rDNA from plasmids...
Ribosomal RNA (rRNA) production represents the most active transcription in cell. Synthesis of large rRNA precursors (35-47S) can be achieved by up to 150 polymerase I (Pol I) enzymes simultaneously transcribing each gene. In this paper, we present recent advances made understanding regulatory mechanisms that control elongation. Built-in Pol elongation factors, such as Rpa34/Rpa49 budding yeast and PAF53/CAST humans, are instrumental extremely high rate per intrinsically linked chromatin...
The association of RNA polymerase III (Pol III)-transcribed genes with nucleoli seems to be an evolutionarily conserved property the spatial organization eukaryotic genomes. However, recent studies global chromosome architecture in budding yeast have challenged this view. We used live-cell imaging determine intranuclear positions 13 Pol III-transcribed genes. frequency nucleolus and nuclear periphery depends on linear genomic distance from tethering elements-centromeres or telomeres....
Most transcriptional activity of exponentially growing cells is carried out by the RNA Polymerase I (Pol I), which produces a ribosomal (rRNA) precursor. In budding yeast, Pol multimeric enzyme with 14 subunits. Among them, Rpa49 forms Rpa34 I-specific heterodimer (homologous to PAF53/CAST in human might be responsible for specific functions I. Previous studies provided insight involvement initiation, elongation, docking and releasing Rrn3, an essential transcription factor. Here, we took...
To study the nuclear export of preribosomes, ribosomal RNAs were detected by in situ hybridization using fluorescence and EM, yeast Saccharomyces cerevisiae. In wild-type cells, semiquantitative analysis shows that distributions pre-40S pre-60S particles nucleolus nucleoplasm are distinct, indicating uncoordinated transport two subunits within nucleus. cells defective for activity GTPase Gsp1p/Ran, precursors accumulate whole This phenotype is reproduced with pre-rRNA processing, whereas...
A collection of yeast strains surviving with mutant 5S RNA has been constructed. The presented alterations the nucleolar structure, less granular component, and a delocalization 25S rRNA throughout nucleoplasm. mutations affected helix I resulted in decreased amounts stable ribosomal 60S subunits. shortage subunits was due to specific defect processing 27SB precursor that gives rise mature 5.8S rRNA. rate pre-rRNA specifically delayed, whereas 27SA 20S were processed at normal rate....
Spatial organisation of chromosomes is a determinant genome stability and required for proper mitotic segregation. However, visualization individual chromatids in living cells quantification their geometry, remains technically challenging. Here, we used live cell imaging to quantitate the three-dimensional conformation yeast Saccharomyces cerevisiae ribosomal DNA (rDNA). rDNA confined within nucleolus composed about 200 copies representing 10% genome. To fluorescently label cells, generated...
Nonribosomal nucleolar protein gar2 is required for 18S rRNA and 40S ribosomal subunit production in Schizosaccharomyces pombe. We have investigated the consequences of absence each structural domain on cell growth, production, structure. Deletion RNA-binding domains (RBDs) causes stronger inhibition growth accumulation than whole protein, suggesting that other factors may be titrated by its remaining N-terminal basic/acidic serine-rich domain. These drastic functional defects correlate with...