Publications by authors named "Flibotte S"

The reversible lipid modification protein S-palmitoylation can dynamically modify the localization, diffusion, function, conformation and physical interactions of substrate proteins. Dysregulated S-palmitoylation is associated with a multitude of human diseases including brain and metabolic disorders, viral infection and cancer. However, the diverse expression patterns of the genes that regulate palmitoylation in the broad range of human cell types are currently unexplored, and their expression in commonly used cell lines that are the workhorse of basic and preclinical research are often overlooked when studying palmitoylation dependent processes.

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Genetic balancers in are complex variants that allow lethal or sterile mutations to be stably maintained in a heterozygous state by suppressing crossover events. Balancers constitute an invaluable tool in the scientific community and have been widely used for decades. The first/traditional balancers were created by applying X-rays, UV, or gamma radiation on strains, generating random genomic rearrangements.

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Dynamic protein S-palmitoylation is critical for neuronal function, development, and synaptic plasticity. Synaptic activity-dependent changes in palmitoylation have been reported for a small number of proteins. Here, we characterized the palmitoylome in the hippocampi of male mice before and after context-dependent fear conditioning.

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Virus protein-linked genome (VPg) proteins are required for replication. VPgs are duplicated in a subset of RNA viruses however their roles are not fully understood and the extent of viral genomes containing VPg copies has not been investigated in detail. Here, we generated a novel bioinformatics approach to identify VPg sequences in viral genomes using hidden Markov models (HMM) based on alignments of dicistrovirus VPg sequences.

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Retrograde bone morphogenetic protein (BMP) signaling at the Drosophila neuromuscular junction (NMJ) has served as a paradigm to study TGF-β-dependent synaptic function and maturation. Yet, how retrograde BMP signaling transcriptionally regulates these functions remains unresolved. Here, we uncover a gene network, enriched for neurotransmission-related genes, that is controlled by retrograde BMP signaling in motor neurons through two Smad-binding cis-regulatory motifs, the BMP-activating (BMP-AE) and silencer (BMP-SE) elements.

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Viral protein genome-linked (VPg) protein plays an essential role in protein-primed replication of plus-stranded RNA viruses. VPg is covalently linked to the 5' end of the viral RNA genome via a phosphodiester bond typically at a conserved amino acid. Whereas most viruses have a single VPg, some viruses have multiple VPgs that are proposed to have redundant yet undefined roles in viral replication.

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Protein -palmitoylation is a reversible post-translational lipid modification that plays a critical role in neuronal development and plasticity, while dysregulated -palmitoylation underlies a number of severe neurological disorders. Dynamic -palmitoylation is regulated by a large family of ZDHHC palmitoylating enzymes, their accessory proteins, and a small number of known de-palmitoylating enzymes. Here, we curated and analyzed expression data for the proteins that regulate -palmitoylation from publicly available RNAseq datasets, providing a comprehensive overview of their distribution in the mouse nervous system.

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Background: Hyperinsulinemia is independently associated with increased risk and mortality of pancreatic cancer. We recently reported that genetically reduced insulin production resulted in ~ 50% suppression of pancreatic intraepithelial neoplasia (PanIN) precancerous lesions in mice. However, only female mice remained normoglycemic, and only the gene dosage of the rodent-specific Ins1 alleles was tested in our previous model.

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During nervous system development, axons navigate complex environments to reach synaptic targets. Early extending axons must interact with guidance cues in the surrounding tissue, while later extending axons can interact directly with earlier "pioneering" axons, "following" their path. In Caenorhabditis elegans, the AVG neuron pioneers the right axon tract of the ventral nerve cord.

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Article Synopsis
  • Insulin receptor (Insr) was deleted specifically in β-cells of male and female mice to examine its role in insulin resistance, revealing sex-specific differences.
  • RNA-seq analysis indicated that Insr loss led to increased action potential and calcium frequencies in female β-cells, but not in males, while only male islets showed reduced ATP production.
  • Deletion of Insr improved glucose tolerance, particularly in female mice, but effects were muted in older males and those on a high-fat diet, indicating that overall insulin resistance may mask the impacts of β-cell specific insulin resistance.
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We used whole-genome sequencing (WGS) data from a strain homozygous for the reciprocal translocation to identify its breakpoints molecularly. The translocation structure is fairly straightforward, with only minor secondary rearrangement in addition to the primary breakpoints. The graphical representation below depicts the two half-translocations for ease of conceptualization.

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We used whole-genome sequencing (WGS) data from a number of balanced lethal strains in to show that the crossover suppressor is an inversion. The rearrangement is complex, with a large primary inversion that contains several other smaller inverted regions. The graphical representation below depicts these various rearrangements for ease of conceptualization.

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Objective: Neurofibromatosis 1 (NF1) is a rare autosomal dominant disease that causes the dysregulated growth of Schwann cells. Most reported studies of brain morphology in NF1 patients have included only children, and clinical implications of the observed changes later in life remain unclear. In this study, we used MRI to characterize brain morphology in adults with NF1.

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Article Synopsis
  • * Researchers isolated two microorganisms from oil sands tailings, analyzing their genetic activity and biochemical functions to uncover how these bacteria metabolize and detoxify NAFCs.
  • * The study showed that the microorganisms function differently when alone compared to when they are in a co-culture, with the latter exhibiting a faster degradation rate for NAFCs, paving the way for potential enhancements in microbial engineering for environmental clean-up.
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It has been estimated that 15%-30% of the ∼20,000 genes in C. elegans are essential, yet many of these genes remain to be identified or characterized. With the goal of identifying unknown essential genes, we performed whole-genome sequencing on complementation pairs from legacy collections of maternal-effect lethal and sterile mutants.

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Objectives: Type 1 diabetes is characterized by the autoimmune destruction of insulin-secreting beta cells. Genetic variants upstream at the insulin (INS) locus contribute to ∼10% of type 1 diabetes heritable risk. Previous studies showed an association between rs3842753 C/C genotype and type 1 diabetes susceptibility, but the molecular mechanisms remain unclear.

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Premature termination codons (PTC) cause over 10% of genetic disease cases. Some aminoglycosides that bind to the ribosome decoding center can induce PTC readthrough and restore low levels of full-length functional proteins. However, concomitant inhibition of protein synthesis limits the extent of PTC readthrough that can be achieved by aminoglycosides like G418.

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The dicistrovirus intergenic region internal ribosome entry site (IGR IRES) uses an unprecedented, streamlined mechanism whereby the IRES adopts a triple-pseudoknot (PK) structure to directly bind to the conserved core of the ribosome and drive translation from a non-AUG codon. The origin of this IRES mechanism is not known. Previously, a partial fragment of a divergent dicistrovirus RNA genome, named ancient Northwest territories cripavirus (aNCV), was extracted from 700-year-old caribou feces trapped in a subarctic ice patch.

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The translation machinery is composed of a myriad of proteins and RNAs whose levels must be coordinated to efficiently produce proteins without wasting energy or substrate. However, protein synthesis is clearly not always perfectly tuned to its environment, as disruption of translation machinery components can lengthen lifespan and stress survival. While much has been learned from bacteria and yeast about translational regulation, much less is known in metazoans.

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Retrograde BMP signaling and canonical pMad/Medea-mediated transcription regulate diverse target genes across subsets of efferent neurons, to differentiate neuropeptidergic neurons and promote motor neuron terminal maturation. How a common BMP signal regulates diverse target genes across many neuronal subsets remains largely unresolved, although available evidence implicates subset-specific transcription factor codes rather than differences in BMP signaling. Here we examine the regulatory mechanisms restricting BMP-induced neuropeptide expression to Tv4-neurons.

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Glucolipotoxicity following nutrient overload causes cardiomyocyte injury by inhibiting TFEB and suppressing lysosomal function. We ascertained whether in addition to the amount, the type of fatty acids (FAs) and duration of FA exposure regulate TFEB action and dictate cardiomyocyte viability. Saturated FA, palmitate, but not polyunsaturated FAs decreased TFEB content in a concentration- and time-dependent manner in cardiomyocytes.

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New anticancer therapeutics require extensive characterization to identify endogenous and exogenous factors affecting efficacy, to measure toxicity and mutagenicity, and to determine genotypes that result in therapeutic sensitivity or resistance. We used as a platform with which to characterize properties of the anticancer therapeutic CX-5461. To understand the processes that respond to CX-5461-induced damage, we generated pharmacogenetic profiles for a panel of DNA replication and repair mutants with common DNA-damaging agents for comparison with the profile of CX-5461.

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The mechanistic basis for the biogenesis of peptide hormones and growth factors is poorly understood. Here, we show that the conserved endoplasmic reticulum membrane translocon-associated protein α (TRAPα), also known as signal sequence receptor 1, plays a critical role in the biosynthesis of insulin. Genetic analysis in the nematode and biochemical studies in pancreatic β cells reveal that TRAPα deletion impairs preproinsulin translocation while unexpectedly disrupting distal steps in insulin biogenesis including proinsulin processing and secretion.

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Background Fatty acid (FA) provision to the heart is from cardiomyocyte and adipose depots, plus lipoprotein lipase action. We tested how a graded reduction in insulin impacts the source of FA used by cardiomyocytes and the cardiac adaptations required to process these FA. Methods and Results Rats injected with 55 (D55) or 100 (D100) mg/kg streptozotocin were terminated after 4 days.

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