Project description:RIL-seq experiment of EPEC hfq-flag mutant, in activating- conditions:growth on DMEM at 37°C to mid exponential growth phase (e.g., OD600=0.3). In these conditions EPEC strongly expresses its major virulence components, T3SS and BFP, mimicking infection. Non-activating conditions: overnight growth of static culture on LB medium at 37°C where virulence factors are not expressed. RIL-seq experiments are designed to reveal the interactions of sRNA and their targets.
Project description:Compared the transcriptome of wild type EPEC with that of an isogenic Δhfq mutant. Comparing activating- conditions:growth on DMEM at 37°C to mid exponential growth phase (e.g., OD600=0.3). In these conditions EPEC strongly expresses its major virulence components, T3SS and BFP, mimicking infection. Non-activating conditions: overnight growth of static culture on LB medium at 37°C where virulence factors are not expressed.
Project description:The evolutionarily conserved POT1 protein binds the single stranded G-rich telomeric DNA and has been implicated in telomeric DNA maintenance and the suppression of DNA damage checkpoint signaling. Here, we explore human POT1 function through genetics and proteomics discovering that the complete absence of POT1 leads to severe telomere maintenance defects that had not been anticipated from previous depletion studies. We determine the telomeric proteome upon POT1-loss by implementing an improved telomeric chromatin isolation protocol. Using quantitative proteomics by tandem mass tags (TMT) we identified a large set of proteins involved in nucleic acid metabolism that engage with telomeres upon loss of POT1. Inactivation of the homology directed repair machinery suppresses POT1-loss mediated telomeric DNA defects. Our results unravel as major function of human POT1 the suppression of telomere instability induced by homology directed repair.
Project description:Whole Exome sequencing of two patients with Cardiac angiosarcoma in Li-Fraumeni-like families discovers that a mutation in the pot1 gene is responsible for cardiac angiosarcoma in tp53-negative li-fraumeni-like families
Project description:Telomere protection 1 (POT1) is an important subunit in the shelterin complex, considered the telomere protector. POT1 dysfunction may lead to telomere length dysregulation and genomic instability. Both germline and somatic POT1 mutations have been identified in CLL patients, suggesting the development of the disease. This study aimedto evaluate the occurrence of POT1 mutations throughout CLL's progression and determine their prognostic significance.
Project description:T-cell acute lymphoblastic leukaemia (T-ALL) is a haematological malignancy commonly driven by NOTCH1 activating mutations. A concomitant feature associated with NOTCH1 mutations is heightened oxidative metabolism enabling the exponential proliferation of T-ALL blasts. As such, targeting mitochondrial metabolism in T-ALL is an attractive therapeutic avenue. Canagliflozin (cana) is an FDA-approved sodium glucose co-transporter 2 inhibitor with known off-target effects on complex I and glutamate dehydrogenase. To date, the effects of cana on T-ALL are not known. Here, we show that cana possesses potent anti-leukaemic effects underpinned by proliferative defects, cell cycle disruption and apoptosis. These anti-leukaemic effects, driven by cana, are attributed to a perturbed tricarboxylic acid (TCA) cycle and mitochondrial metabolism and elevated mitochondrial ROS. Proteomic analysis revealed that cana treatment resulted in a compensatory increase in the expression of ATF4 targets, including upregulation of serine biosynthesis pathway and one-carbon metabolism enzymes. As such, restriction of serine and glycine synergized with cana treatment, further enhancing anti-leukaemic effects. Collectively, our study reveals cana creates a metabolic vulnerability that can be further exploited via dietary manipulation to treat T-ALL
Project description:Telomeres safeguard the genome, acting as sentinels of oxidative stress and preventing chromosome ends from eliciting a DNA damage response. PROTECTION OF TELOMERES 1 (POT1) is a highly conserved telomere protein, essential for chromosome integrity and telomeric DNA replication. Arabidopsis thaliana encodes two divergent POT1 paralogs: AtPOT1a stimulates telomerase activity, but AtPOT1b function is unknown. Here we show that AtPOT1b modulates reactive oxygen species (ROS) homeostasis. Oxidative stress induces AtPOT1b expression and telomeric accumulation, while AtPOT1b inactivation elevates ROS, increases telomeric and genome-wide oxidation, and causes stochastic telomere length changes. To address how AtPOT1b controls ROS, we report its localization in nuclei and peroxisomes, and association with catalases and peroxidases that enhance ROS scavenging. Impairing AtPOT1b-CAT2 interaction increases ROS accumulation and telomeric oxidation. Moss or human POT1 rescues ROS overaccumulation in Arabidopsis pot1b mutants, but not telomere deficiency in pot1a pot1b mutants, supporting a conserved role for POT1 in modulating ROS homeostasis and genome stability, distinct from canonical telomeric functions.