Publications by authors named "Celine Maeder"

Background: Mitochondrial disease is a family of genetic disorders characterized by defects in the generation and regulation of energy. Epilepsy is a common symptom of mitochondrial disease, and in the vast majority of cases, refractory to commonly used antiepileptic drugs. Ferroptosis is a recently-described form of iron- and lipid-dependent regulated cell death associated with glutathione depletion and production of lipid peroxides by lipoxygenase enzymes.

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The proper assembly of neural circuits depends on the process of synaptogenesis, or the formation of synapses between partner neurons. Using the dopaminergic PDE neurons in C. elegans, we developed an in vivo system to study the earliest steps of the formation of en passant presynaptic specializations behind an extending growth cone.

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Synaptic vesicle and active zone proteins are required for synaptogenesis. The molecular mechanisms for coordinated synthesis of these proteins are not understood. Using forward genetic screens, we identified the conserved THO nuclear export complex (THOC) as an important regulator of presynapse development in C.

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Abnormal axonal transport is associated with neuronal disease. We identified a role for DHC-1, the C. elegans dynein heavy chain, in maintaining neuronal cargo distribution.

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Here, we report on a novel PCR targeting-based strategy called 'PCR duplication' that enables targeted duplications of genomic regions in the yeast genome using a simple PCR-based approach. To demonstrate its application we first duplicated the promoter of the FAR1 gene in yeast and simultaneously inserted a GFP downstream of it. This created a reporter for promoter activity while leaving the FAR1 gene fully intact.

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Neuronal trafficking is crucial to the formation and dynamics of presynaptic and postsynaptic structures and the development and maintenance of axonal and dendritic processes. The mechanism for delivering specific organelles and synaptic molecules in axons and dendrites primarily depends on molecular motor proteins that move along the cytoskeleton. Adaptor proteins, regulatory molecules and local signaling pathways provide additional layers of specificity and control over bidirectional movement, polarized transport and cargo delivery.

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During synapse development, synaptic proteins must be targeted to sites of presynaptic release. Directed transport as well as local sequestration of synaptic vesicle precursors (SVPs), membranous organelles containing many synaptic proteins, might contribute to this process. Using neuron-wide time-lapse microscopy, we studied SVP dynamics in the DA9 motor neuron in Caenorhabditis elegans.

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The location, size, and number of synapses critically influence the specificity and strength of neural connections. In axons, synaptic vesicle (SV) and active zone (AZ) proteins are transported by molecular motors and accumulate at discrete presynaptic loci. Little is known about the mechanisms coordinating presynaptic protein transport and deposition to achieve proper distribution of synaptic material.

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Nervous systems are built of a myriad of neurons connected by an even larger number of synapses. While it has been long known that neurons specifically select their synaptic partners among many possible choices during development, we only begin to understand how they make those decisions. Recent findings have started to elucidate the molecular mechanisms underlying synaptic target selection including positive as well as negative cues from synaptic partners, intermediate targets and surrounding tissues.

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Presynaptic assembly requires the packaging of requisite proteins into vesicular cargoes in the cell soma, their long-distance microtubule-dependent transport down the axon, and, finally, their reconstitution into functional complexes at prespecified sites. Despite the identification of several molecules that contribute to these events, the regulatory mechanisms defining such discrete states remain elusive. We report the characterization of an Arf-like small G protein, ARL-8, required during this process.

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Polarized trafficking of synaptic proteins to axons and dendrites is crucial to neuronal function. Through forward genetic analysis in C. elegans, we identified a cyclin (CYY-1) and a cyclin-dependent Pctaire kinase (PCT-1) necessary for targeting presynaptic components to the axon.

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Precise control over organelle shapes is essential for cellular organization and morphogenesis. During yeast meiosis, prospore membranes (PSMs) constitute bell-shaped organelles that enwrap the postmeiotic nuclei leading to the cellularization of the mother cell's cytoplasm and to spore formation. Here, we analysed how the PSMs acquire their curved bell-shaped structure.

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Signal transduction through mitogen-activated protein kinase (MAPK) cascades is thought to occur through the assembly of macromolecular complexes. We quantified the abundance of complexes in the cytoplasm among the MAPKs Ste11, Ste7, Fus3 and the scaffold protein Ste5 in yeast pheromone signalling using fluorescence cross-correlation spectroscopy (FCCS). Significant complex concentrations were observed that remained unchanged on pheromone stimulation, demonstrating that global changes in complex abundances do not contribute to the transmission of signal through the cytoplasm.

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During sporulation in Saccharomyces cerevisiae, the four daughter cells (spores) are formed inside the boundaries of the mother cell. Here, we investigated the dynamics of spore assembly and the actin cytoskeleton during this process, as well as the requirements for filamentous actin during the different steps of spore formation. We found no evidence for a polarized actin cytoskeleton during sporulation.

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