Jeroen Dobbelaere

University of Vienna | UniWien · Max Perutz Laboratories

Centriolar satellites are cytoplasmic particles found in the vicinity of centrosomes and cilia whose functional contribution to the formation of these cellular structures has long been unclear. By characterizing the main scaffolding component of satellites, PCM1 or Combover in Drosophila , we show that satellites are not involved in cellular traffi...

Cilia are cellular projections that perform sensory and motile functions in eukaryotic cells. A defining feature of cilia is that they are evolutionarily ancient, yet not universally conserved. In this study, we have used the resulting presence and absence pattern in the genomes of diverse eukaryotes to identify a set of 386 human genes associated...

Addressing climate change and sustainability starts with individuals and moves up to institutional change. Here is what we as scientists in the life sciences can do to enact change.

Cilia are membrane-surrounded sensory cellular organelles that can also create motion to move fluids or propel the cell to which they are attached. New work shows that, whereas transition fibers are essential for cilia attachment to the membrane in most systems studied, transition fibers in Drosophila are only involved in cilia extension after dock...

Cilia are cellular projections that perform sensory and motile functions in eukaryotic cells. A defining feature of cilia is that they are evolutionarily ancient yet not universally conserved. In this study we have used the resulting presence and absence pattern in the genomes of diverse eukaryotes to identify a set of 386 human genes associated wi...

Climate change is the greatest challenge of our time, and drastic climate action is needed urgently across industries and sectors to prevent the worst in terms of consequences. Although academic research brings great benefits to society, it leaves behind a considerable environmental footprint at the same time. This is particularly true for lab rese...

Although universities have been leading climate science for decades, most have not taken drastic climate action in their own operations. Sustainable transformation of the university sector requires accounting for all scopes 1–3 emissions and setting science-based reduction targets. It is high time for universities to practice what they preach and m...

Centrioles are highly elaborate microtubule-based structures responsible for the formation of centrosomes and cilia. Despite considerable variation across species and tissues within any given tissue, their size is essentially constant [1, 2]. While the diameter of the centriole cylinder is set by the dimensions of the inner scaffolding structure of...

Centrioles are highly elaborate microtubule-based structures responsible for the formation of centrosomes and cilia. Despite considerable variation across species and tissues, within any given tissue their size is essentially constant. While the diameter of the centriole cylinder is set by the dimensions of the inner scaffolding structure of the ca...

Microtubule-organizing centers (MTOCs) nucleate microtubules that can grow autonomously in any direction. To generate bundles of parallel microtubules originating from a single MTOC, the growth of multiple microtubules needs to coordinated, but the underlying mechanism is unknown. Here, we show that a conserved two-component system consisting of th...

Centrosomes act as the major microtubule organizing centers in animal cells. To fully understand how the centrosome functions, a detailed analysis of its principal structural components and regulators is needed. Genome-wide RNA interference (RNAi) allows for comprehensive screening of all components. Drosophila tissue culture cells provide an attra...

Centrosomes are important cell organizers. They consist of a pair of centrioles surrounded by pericentriolar material (PCM) that expands dramatically during mitosis-a process termed centrosome maturation. How centrosomes mature remains mysterious. Here, we identify a domain in Drosophila Cnn that appears to be phosphorylated by Polo/Plk1 specifical...

CP110 is a conserved centriole protein implicated in the regulation of cell division, centriole duplication, and centriole length and in the suppression of ciliogenesis. Surprisingly, we report that mutant flies lacking CP110 (CP110Δ) were viable and fertile and had no obvious defects in cell division, centriole duplication, or cilia formation. We...

Dgp71WD/Nedd1 proteins are essential for mitotic spindle formation. In human cells, Nedd1 targets γ-tubulin to both centrosomes and spindles, but in other organisms the function of Dgp71WD/Nedd1 is less clear. In Drosophila cells, Dgp71WD plays a major part in targeting γ-tubulin to spindles, but not centrosomes, while in Xenopus egg extracts, Nedd...

centrosomes are major microtubule organizing centers in animal cells, and they comprise a pair of centrioles surrounded by an amorphous pericentriolar material (PCM). Centrosome size is tightly regulated during the cell cycle, and it has recently been shown that the two centrosomes in certain stem cells are often asymmetric in size. There is compel...

In Caenorhabditis elegans, five proteins are required for centriole duplication: SPD-2, ZYG-1, SAS-5, SAS-6, and SAS-4. Functional orthologues of all but SAS-5 have been found in other species. In Drosophila melanogaster and humans, Sak/Plk4, DSas-6/hSas-6, and DSas-4/CPAP-orthologues of ZYG-1, SAS-6, and SAS-4, respectively-are required for centri...

Recent studies have identified a conserved "core" of proteins that are required for centriole duplication. A small number of additional proteins have recently been identified as potential duplication factors, but it is unclear whether any of these proteins are components of the core duplication machinery. In this study, we investigate the function...

Author Summary A major goal of the cell cycle is to accurately separate the duplicated chromosomes between two daughter cells. To achieve this, a pair of centrosomes organise a bipolar spindle made of microtubules; the chromosomes line up on the spindle and are then separated to the two spindle poles. Centrosomes are also required for the formatio...

Validation of the Genes Selected in the Primary Screen (75 KB PDF)

List of dsRNAs Used in the Secondary Screening (80 KB PDF)

Quantitation of PCM Size after Protein Depletion A bar chart showing the average PCM size in S2R+ cells treated with dsRNAs against the proteins identified in our screen. The control PCM size was assigned a value of 100% (GFP—grey), and error bars represent the standard error (SE). Red bars represent genes involved in centriole duplication; green b...

Statistical Analysis of the Primary Screen Using CellProfiler and CellHTS (A) A graph showing the “raw” average number of centrosomes (centrosome index) per mitotic cell in each 384-well plate as measured in CellProfiler. Error bars represent the distribution per plate. (B) A graph showing the “normalised” number of centrosomes per mitotic cell in...

List of GFP-Tagged Proteins Analysed (33 KB PDF)

List of All the Genes Identified in the Primary Genome-Wide Screen as Being Defective in Centrosome Function (35 KB XLS)

A Failure in Centrosome Separation Is the Main Phenotype Observed in aurora A Mutant Brain Cells (A–D) Wild-type (w67) or aurora-A mutant (aure200/e209) 3rd instar larval brains were stained with anti–α-tubulin (red) and anti-Cnn (green) antibodies and counterstained with Hoechst (blue). (E) Graph depicting the centriole numbers in mitotic cells in...

Overview of the Primary and Secondary Screening and GFP-Tagging for Each Gene Identified in the Screen (A) A representative picture from the primary screen using a 20× objective. Colchicine arrested S2R+ cells stained for Cnn (green), p-H3 (red) and DNA (blue). (B) Detailed RNAi analysis to distinguish between genes involved in centriole duplicatio...

List of Genes Excluded from the Screen Due to Lack of Cells or the Absence Of Mitotic Cells (34 KB PDF)

The Overexpression of Some Centriole Components in S2 cells Produces Extra Cytoplasmic Dots (A) Images of a cell from several stably transfected S2 cell lines overexpressing a GFP-tagged protein (green) from the Ubq promoter (as labelled in each panel) are shown here. Cells were stained with anti–DSas-4 antibodies (red) to reveal the localisation o...

CellProfiler Pipeline Used to Identify the Number of Centrosomes per Mitotic Cell (19 KB TXT)

During anaphase, spindle elongation pulls sister chromatids apart until each pair is fully separated. In turn, cytokinesis cleaves the cell between the separated chromosomes. What ensures that cytokinesis proceeds only after that all chromosome arms are pulled out of the cleavage plane was unknown. Here, we show that a signaling pathway, which we c...

SCF-type (SCF: Skp1-Cullin-F-box protein complex) E3 ligases regulate ubiquitin-dependent degradation of many cell cycle regulators, mainly at the G1/S transition. Here, we show that SCF(Grr1) functions during cytokinesis by degrading the PCH protein Hof1. While Hof1 is required early in mitosis to assemble a functional actomyosin ring, it is speci...

During cytokinesis, furrow ingression and plasma membrane fission irreversibly separate daughter cells. How actomyosin ring assembly and contraction, vesicle fusion, and abscission are spatially coordinated was unknown. We found that during cytokinesis septin rings, located on both sides of the actomyosin ring, acted as barriers to compartmentalize...

Septins are GTPases involved in cytokinesis. In yeast, they form a ring at the cleavage site. Using FRAP, we show that septins are mobile within the ring at bud emergence and telophase and are immobile during S, G2, and M phases. Immobilization of the septins is dependent on both Cla4, a PAK-like kinase, and Gin4, a septin-dependent kinase that can...

Enthält versch. Sonderdr. Diss. no. 15762 nat. sc. SFIT Zurich. Literaturverz.