Project description:One microbial organism always contains multiple DNA modification systems as defense strategies or epigenetic controls. Here, we describe crosstalk between two distinct DNA modifications with different target sequence motif: DNA phosphorothioation (PT, GPSAAC/GPSTTC by DndACDE proteins) and N6-methyl-adenine methylation (m6A, G6mATC by Dam protein). By using a newly developed DNA modification sequencing method PT nick-seq, we found that half of PT modifications change from GAAC/GTTC to GATC sites after bacteria have lost Dam.
Project description:Endogenous and exogenous chemical modifications in DNA have profound influences on genome function. We have developed a novel technology, Nick-seq, for mapping variety of DNA chemical modifications across the genomes at single-nucleotide resolution, by which we achieved quantitative profiling of single-strand breaks, phosphorothioate modifications, and oxidative DNA damage sites. This method is applicable for mapping of any DNA metabolism events that are involved in or can be converted, enzymatically or chemically, to DNA strand breaks such as DNA modifications, damages, genome replication, and chromatin structures.
Project description:Endogenous and exogenous chemical modifications in DNA have profound influences on genome function. We have developed a novel technology, Nick-seq, for mapping variety of DNA chemical modifications across the genomes at single-nucleotide resolution, by which we achieved quantitative profiling of single-strand breaks, phosphorothioate modifications, and oxidative DNA damage sites. This method is applicable for mapping of any DNA metabolism events that are involved in or can be converted, enzymatically or chemically, to DNA strand breaks such as DNA modifications, damages, genome replication, and chromatin structures.
Project description:Pt-ttpy (tolyl terpyridin-Pt complex) covalently binds to G-quadruplex (G4) structures in vitro and to telomeres in cellulo via its Pt moiety. Here, we identified its targets in the human genome, in comparison to Pt-tpy, its derivative without G4 affinity, and cisplatin. Pt-ttpy, but not Pt-tpy, induces the release of the shelterin protein TRF2 from telomeres concomitantly to the formation of DNA damage foci at telomeres but also at other chromosomal locations. -H2AX chromatin immunoprecipitation (ChIP-seq) after treatment with Pt-ttpy or cisplatin revealed accumulation in G- and A-rich tandemly repeated sequences, but not particularly in potential G4 forming sequences. Collectively, Pt-ttpy presents dual targeting efficiency on DNA, by inducing telomere dysfunction and genomic DNA damage at specific loci.
Project description:Endogenous and exogenous chemical modifications in DNA have profound influences on genome function. We have developed a novel technology, Nick-seq, for mapping variety of DNA chemical modifications across the genomes at single-nucleotide resolution, by which we achieved quantitative profiling of single-strand breaks, phosphorothioate modifications, and oxidative DNA damage sites. This method is applicable for mapping of any DNA metabolism events that are involved in or can be converted, enzymatically or chemically, to DNA strand breaks such as DNA modifications, damages, genome replication, and chromatin structures.
Project description:To capture proteins that exhibit differential binding with PT- and non-PT-modified DNA in vivo, we performed pull-down assays using biotinylated DNA probes and the cell lysate of S. enterica serovar Cerro 87 that contains the dndBCDE-dndFGH module. For these experiments, we used two 30 bp DNA probes, B12 and B34, which share the same DNA sequences but possess PT-modified 5’-GPSAAC-3’/5’-GPSTTC-3’ and non-PT-modified 5’-GAAC-3’/5’-GTTC-3’ motifs, respectively.
Project description:Purpose: We investigate the evolutionary footprints of a bacteria-plasmid association consisting of Escherichia coli K-12 MG1655 and plasmid RP4 undergoing a long-term sub-MIC antibiotic stress. Methods: Bacterial mRNA profiles of evolved RP4-carrying strains (E:H:p) and ancestral RP4-carrying strains (A:H:p) were generated by deep sequencing on an Illumina Hiseq platform. The sequence reads that passed quality filters were analyzed by Burrows–Wheeler Aligner (BWA), followed by ANOVA (ANOVA) and TopHat followed by Cufflinks. qRT–PCR validation was performed using TaqMan and SYBR Green assays Results: Using an optimized data analysis workflow, we mapped about 15 million sequence reads of E:H:p and 12 million sequence reads of A:H:p to the E. coli MG1655 genome (GCF_000801205.1) and differential expressed genes were identified with TopHat workflow. RNA-seq data showed that approximately 15% of the transcripts showed differential expression between the E:H:p and A:H:p strains, with a fold change ≥1 and p value <0.005. Altered expression of 26 genes was confirmed with qRT–PCR, demonstrating the high degree of sensitivity of the RNA-seq method. Data analysis with bowtie and TopHat workflows provided complementary insights in transcriptome profiling. Conclusions: Our study showed the coevolved bacteria-plasmid pairs has colonization traits superior to the wild-type parent strain. Antibiotic stress was necessary for bacterial evolution and evolved strains mostly employed transcriptional modifications to reduce plasmid-related cost in evolutionary adaptations. Several genes related to chromosome-encoded efflux pumps were transcriptionally upregulated, while most plasmid-harboring genes were downregulated based on RNA gene sequencing. These transcriptional modifications endowed evolved strains with resistant phenotype modifications, including the enhanced bacterial growth and biofilm formation.