A5064150176- Bacterial Genetics and Biotechnology
- Bacteriophages and microbial interactions
- Genomics and Phylogenetic Studies
- DNA Repair Mechanisms
- Antibiotic Resistance in Bacteria
- Bacterial biofilms and quorum sensing
- RNA and protein synthesis mechanisms
- Enzyme Structure and Function
- Escherichia coli research studies
- Gut microbiota and health
- Mycobacterium research and diagnosis
- Lipid Membrane Structure and Behavior
- Vibrio bacteria research studies
- Healthcare and Environmental Waste Management
- Tuberculosis Research and Epidemiology
- Genomics and Chromatin Dynamics
- Biochemical and Structural Characterization
- Cancer Research and Treatments
- Legume Nitrogen Fixing Symbiosis
- Endoplasmic Reticulum Stress and Disease
- Reproductive tract infections research
- Microbial Metabolic Engineering and Bioproduction
- Plant Stress Responses and Tolerance
- Acute Myeloid Leukemia Research
- Protist diversity and phylogeny
University of Geneva
2012-2024
Aix-Marseille Université
2010-2012
Institut de Microbiologie de la Méditerranée
2010-2012
Laboratoire de Chimie Bactérienne
2007-2012
Centre National de la Recherche Scientifique
2007-2012
Institut de Biologie Structurale
2007
A single ATPase powers extension and retraction of a broadly distributed class type IV pili.
ParB-like CTPases mediate the segregation of bacterial chromosomes and low-copy number plasmids. They act as DNA-sliding clamps that are loaded at parS motifs in centromere target DNA molecules spread laterally to form large nucleoprotein complexes serving docking points for machinery. Here, we solve crystal structures ParB pre- post-hydrolysis state illuminate catalytic mechanism nucleotide hydrolysis. Moreover, identify conformational changes underlie CTP- parS-dependent closure clamps....
What are the minimal requirements to sustain an asymmetric cell cycle? Here we use mathematical modelling and forward genetics reduce cycle its simplest, primordial components. In Alphaproteobacterium Caulobacter crescentus, progression is believed be controlled by a cyclical genetic circuit comprising four essential master regulators. Unexpectedly, our in silico predicted that one of these regulators, GcrA, fact dispensable. We confirmed this experimentally, finding ΔgcrA cells viable, but...
The emergence of biochemically and genetically tractable host model organisms for infection studies holds the promise to accelerate pace discoveries related evolution innate immunity dissection conserved mechanisms cell-autonomous defenses. Here, we have used system Dictyostelium discoideum / Mycobacterium marinum apply a genome-wide transposon-sequencing experimental strategy reveal comprehensively which mutations confer fitness advantage or disadvantage during compare these similar...
The spatiotemporal regulation of chromosome segregation and cell division in Caulobacter crescentus is mediated by two different P-loop ATPases, ParA MipZ. Both these proteins form dynamic concentration gradients that control the positioning regulatory targets within cell. Their proper localization depends on their nucleotide-dependent cycling between a monomeric dimeric state ability species to associate with nucleoid. In this study, we use combination genetic screening, biochemical...
Summary Beyond its essential roles in ensuring faithful chromosome segregation and genomic stability, the human Smc5/6 complex acts as an antiviral factor. It binds to impedes transcription of extrachromosomal DNA templates; ability which is lost upon chromosomal integration. How distinguishes among different templates unknown. Here we show that, cells, preferentially circular rather than linear DNA. We further that this binding unlikely due differences chromatin composition. Instead,...
ABSTRACT The alphaproteobacterium Caulobacter crescentus thrives in oligotrophic environments and is able to optimally exploit minimal resources by entertaining an intricate network of gene expression control mechanisms. Numerous transcriptional activators repressors have been reported contribute these processes, but only few studies focused on regulation at the post-transcriptional level C. . Small RNAs (sRNAs) are a prominent class regulators bacterial expression, most sRNAs characterized...
We searched for regulators of chromosome replication in the cell cycle model Caulobacter crescentus and found a novel DNA-binding protein (GapR) that selectively aids initiation initial steps partitioning. The binds origin (Cori) has higher-affinity binding to mutated Cori-DNA increases Cori-plasmid vivo. gapR gene expression is essential normal rapid growth sufficient GapR levels are required correct timing replication. Whole genome ChIP-seq identified dynamic distributions GapR, with...
In the absence of oxygen, Escherichia coli can use alternative exogenous electron acceptors, including trimethylamine oxide (TMAO), to generate energy. this study, we showed that in contrast other anaerobic respiratory systems, TMAO reductase (Tor) system was expressed during both aerobiosis and anaerobiosis. By using a torA-lacZ fusion quantitative reverse transcription polymerase chain reaction, established torCAD operon encoding Tor induced presence mainly exponential phase, optimal...
Bacterial growth and division require regulated synthesis of the macromolecules used to expand replicate components cell. Transcription housekeeping genes required for metabolic homeostasis cell proliferation is guided by sigma factor σ70. The conserved CarD-like transcriptional regulator, CdnL, associates with promoter regions where σ70 localizes stabilizes open complex. However, contributions CdnL bacterial physiology are not well understood. Here, we show that Caulobacter crescentus cells...
Protein polarization underlies differentiation in metazoans and bacteria. How symmetric can instate functional asymmetry remains elusive. Here, we show by super-resolution photo-activated localization microscopy edgetic mutations that the bitopic zinc-finger protein ZitP implements specialized developmental functions – pilus biogenesis multifactorial swarming motility while shaping distinct nanoscale (bi)polar architectures asymmetric model bacterium Caulobacter crescentus. Polar assemblage...
KplE1 is one of the 10 prophage regions Escherichia coli K12, located at 2464 kb on chromosome. defective for lysis, but it fully competent excisive recombination. In this study, we have mapped binding sites recombination proteins, namely IntS, TorI, and IHF attL attR, organization these suggests that intasome architecturally different from lambda canonical form. We also measured relative contribution proteins to both integrative by using a quantitative in vitro assay. These experiments show...
φCbK is a B3 morphotype bacteriophage of the Siphoviridae family that infects Caulobacter crescentus, preeminent model system for bacterial cell cycle studies. The last 4 decades research with as genetic and cytological tool to study biology host warrant an investigation phage genome composition. Herein, we report complete sequence highlight unusual features emerged from its annotation. analysis provides new insight into characteristics potential interactions crescentus host, setting stage...
Like other obligate intracellular bacteria, the Chlamydiae feature a compact regulatory genome that remains uncharted owing to poor genetic tractability. Exploiting reduced number of transcription factors (TFs) encoded in chlamydial (pan-)genome as model for TF control supporting lifestyle, we determined conserved landscape specificities by ChIP-Seq (chromatin immunoprecipitation-sequencing) pathogen Waddlia chondrophila. Among 10 TFs, Euo emerged master targeting >100 promoters through...
Temperate phages have the ability to maintain their genome in host, a process called lysogeny. For most, passive replication of phage relies on integration into host's chromosome and becoming prophage. Prophages remain silent absence stress replicate passively within host genome. However, when stressful conditions occur, prophage excises itself resumes viral cycle. Integration excision genomes are mediated by regulated site-specific recombination catalyzed tyrosine serine recombinases. In...
Recombination directionality factors (RDFs), or excisionases, are essential players of prophage excisive recombination. Despite the essentially catalytic role integrase in both integrative and recombination, RDFs required to direct reaction towards excision prevent re-integration genome when entering a lytic cycle. KplE1, HK620 numerous (pro)phages that integrate at same site enterobacteria genomes (such as argW tRNA gene) all share highly conserved recombination module. This module...
Abstract In response to nutrient deprivation, bacteria activate a conserved stress pathway called the stringent (SR). During SR activation in Caulobacter crescentus, SpoT synthesizes secondary messengers guanosine 5′-diphosphate 3′-diphosphate and 5′-triphosphate (collectively known as (p)ppGpp), which affect transcription by binding RNA polymerase (RNAP) down-regulate anabolic genes. (p)ppGpp also impacts expression of genes controlling levels activities their transcriptional regulators....
Many bacteria acquire dissemination and virulence traits in G1-phase. CtrA, an essential conserved cell cycle transcriptional regulator identified the dimorphic alpha-proteobacterium Caulobacter crescentus, first activates promoters late S-phase then mysteriously switches to different target We uncovered a highly determinant DNA-binding domain (DBD) of CtrA uncoupling this promoter switch. also show that it reprograms occupancy stationary cells inducing (p)ppGpp alarmone signal perceived by...
The Alphaproteobacteria show a remarkable diversity of cell cycle-dependent developmental patterns, which are governed by the conserved CtrA pathway. Its central component is DNA-binding response regulator that controlled complex two-component signaling network, mediating distinct transcriptional programs in two offspring. pathway has been studied intensively and was shown to consist an upstream part reads out state downstream integrates signals mediates phosphorylation. However, role this...
The acquisition of multidrug resistance (MDR) determinants jeopardizes treatment bacterial infections with antibiotics. tripartite efflux pump AcrAB-NodT confers adaptive MDR in the polarized α-proteobacterium Caulobacter crescentus via transcriptional induction by first-generation quinolone We discovered that overexpression mutation or exogenous inducers to cephalosporin and penicillin (β-lactam) Combining 2-step mutagenesis-sequencing (Mut-Seq) cephalosporin-resistant point mutants, we...