Marker Frequency analysis on Escherichia coli RecB mutants
Ontology highlight
ABSTRACT: Nucleic Acid Sequencing for the study of division induced double strand breaks in the terminus region of Escherichia coli cells lacking RecBCD DNA repair enzymes.
INSTRUMENT(S): Illumina MiSeq
ORGANISM(S): Escherichia coli str. K-12 substr. MG1655
Project description:Study of the possible existence of a replication fork trap in Vibrio cholerae. 1- FX85: EPV50(WT) grown in M9 minimal medium supplemented with 0.4 % fructose to exponential phase (0.2 OD 650 nm). 2- FX86: EPV50(WT) grown in M9 minimal medium supplemented with 0.4 % fructose to stationary phase (long overnight). 3- FX288: EGV140 (oriL3) grown in M9 minimal medium supplemented with 0.4 % fructose to exponential phase (0.2 OD 650 nm). 4- FX289:EGV140 (oriL3) grown in M9 minimal medium supplemented with 0.4 % fructose to stationary phase (long overnight). 5- FX290: EGV111 (oriR4) grown in M9 minimal medium supplemented with 0.4 % fructose to exponential phase (0.2 OD 650 nm). 6- FX291:EGV111 (oriR4) grown in M9 minimal medium supplemented with 0.4 % fructose to stationary phase (long overnight). 7- FX355:EPV50 (WT) grown in LB medium to exponential phase (0.2 OD 650nm) 8- FX356:EPV50 (WT) grown in LB medium to stationary phase (overnight) 9- FX286:EGV140 (oriL3) grown in LB medium to exponential phase (0.2 OD 650nm) 10- FX287:EGV140 (oriL3) grown in LB medium to stationary phase (overnight) 11- FX292:EGV111 (oriR4) grown in LB medium to exponential phase (0.2 OD 650nm) 12- FX49: MCH1 (WT monochromosome) grown in M9 minimal medium supplemented with 0.4 % fructose to exponential phase (0.2 OD 650 nm). 13- FX48: MCH1 (WT monochromosome) grown in M9 minimal medium supplemented with 0.4 % fructose to stationary phase (long overnight). 14- FX11: EGV369 (oriL3 monochromosome) grown in M9 minimal medium supplemented with 0.4 % fructose to exponential phase (0.2 OD 650 nm). 15- FX12: EGV366 (oriR4 monochromosome) grown in M9 minimal medium supplemented with 0.4 % fructose to exponential phase (0.2 OD 650 nm). 16- FX296 EPV50 M9 Exp 17- FX294 EPV50 M9 Stat 18-FX316 EGV140 M9 Exp 19- FX315 EGV111 M9 Exp 20-FX318 MCH1 M9 Exp 21- FX317 MCH1 M9 Stat 22- FX320 EGV369 M9 Exp 23- FX319 EGV366 M9 Exp Chromosomal DNA was extracted using the Sigma GenElute bacterial genomic DNA kit. 5 μg of DNA were used to generate a genomic library according to Illumina's protocol. The libraries and the sequencing were performed by the High-throughput Sequencing facility of the I2BC (http://www.i2bc.paris-saclay.fr/spip.php?article399〈=en,CNRS, Gif-sur-Yvette, France). Genomic DNA libraries were made with the ‘Nextera DNA library preparation kit’ (Illumina) following the manufacturer’s recommendations. Library quality was assessed on an Agilent Bioanalyzer 2100, using an Agilent High Sensitivity DNA Kit (Agilent technologies). Libraries were pooled in equimolar proportions. 75 bp single reads were generated on an Illumina MiSeq instrument, using a MiSeq Reagent kit V2 (500 cycles) (Illumina), with an expected depth of 217X. Reads were aligned on the in silico reconstituted genome of the cognate strain using BWA software. An in-lab written MATLAB-based script was used to perform marker frequency analysis. Data were normalized by dividing uniquely mapping sequence reads by the total number of reads. Enrichment of uniquely mapping sequence reads in 1 kb non-overlapping windows were calculated and plotted against the chromosomal coordinates.
Project description:Study of the mechanisms of RecB mutant terminus DNA loss in Escherichia coli. FX158: WT MG1655 FX35: recB- FX37: ruvAB- FX51: matP- MIC18: recB- sbcD- sbcC- MIC20: recB- ruvAB- MIC24: matP- recB- MIC25: recA- recB- MIC31: sbcB- sbcD- MIC34: recA- recD- MIC40: linear chromosome MIC41: linear chromosome recB- MIC42: matP- ftsKC- MIC43: matP- ftsKC- recB- MIC48: recA- Cells were grown in M9 minimal medium supplemented with 0.4 % glucose to exponential phase (0.2 OD 650 nm). Chromosomal DNA was extracted using the Sigma GenElute bacterial genomic DNA kit. 5 μg of DNA were used to generate a genomic library according to Illumina's protocol. The libraries and the sequencing were performed by the High-throughput Sequencing facility of the I2BC (http://www.i2bc.paris-saclay.fr/spip.php?article399&lang=en, CNRS, Gif-sur-Yvette, France). Genomic DNA libraries were made with the ‘Nextera DNA library preparation kit’ (Illumina) following the manufacturer’s recommendations. Library quality was assessed on an Agilent Bioanalyzer 2100, using an Agilent High Sensitivity DNA Kit (Agilent technologies). Libraries were pooled in equimolar proportions. 75 bp single reads were generated on an Illumina MiSeq instrument, using a MiSeq Reagent kit V2 (500 cycles) (Illumina), with an expected depth of 217X. An in-lab written MATLAB-based script was used to perform marker frequency analysis. Reads were aligned on the Escherichia coli K12 MG1655 genome using BWA software. Data were normalized by dividing uniquely mapping sequence reads by the total number of reads. Enrichment of uniquely mapping sequence reads in 1 kb non-overlapping windows were calculated and plotted against the chromosomal coordinates.
Project description:YAV20 (E7946 loxP[dciA] SpR lacZ::cre ZeoR), AB14 (YAV20 inv[glmU-mioC]) and AB23 ( YAV20 ΔrecB::CmR) were created by natural transfromation using cognate plasmids. Cells were grown in the M( minimla media supplemented with fructose, with or without arabinose (ara). Genomic DNA was extracted with the Sigma GenElute® bacterial genomic DNA kit to generate a genomic library according to Illumina’s protocol. The libraries and the sequencing were performed by the High-throughput Sequencing facility of the I2BC (https://www.i2bc.paris-saclay.fr/sequencing/ng-sequencing/, CNRS, Gif-sur-Yvette, France). Genomic DNA libraries were made with the ‘Nextera DNA library preparation kit’ (Illumina) following the manufacturer’s recommendations.
Project description:In the bacterium Escherichia coli, RecG directs DNA synthesis during the repair of DNA double-strand breaks by homologous recombination. Chromosomal marker frequency analysis (MFA) following induction of a DSB in the absence and presence of RecG
Project description:In the bacterium Escherichia coli, RecG directs DNA synthesis during the repair of DNA double-strand breaks by homologous recombination.
Project description:S. meliloti strains with a bi- and monopartite genome configuration were constructed by consecutive Cre/lox-mediated site-specific fusions of the secondary replicons. Beside the correct genomic arrangements, these strains and precursors were tested for variations in the nucleotide sequence. Futher, a marker fequency analysis was performed to test if replication is initiated at all origins and to determine the replication termination regions of the triple replicon fusion molecule. To gain the sequence data for these analyses, respective strains were applied to whole genome sequencing using an Illumina MiSeq-System and Oxford Nanopore (MinION) sequencing technology.
Project description:RecBCD protein complex is an important player of DSB repair in bacteria and bacteria that cannot repair DNA double-stranded breaks (DSB) have a low viability. Whole genome sequencing analyses showed a deficit in specific sequences of the chromosome terminus region in recB mutant cells, suggesting terminus DNA degradation during growth. We studied here the phenomenon of terminus DNA loss by 42 whole genome sequencing and microscopy analyses of exponentially growing bacteria. We tested all processes known to take place in the chromosome terminus region for a putative role in DNA loss: replication fork termination, dimer resolution, resolution of catenated chromosomes, and translocation of the chromosome arms in daughter cells during septum formation. None of the mutations that affect these processes prevents the phenomenon. However, we observed that terminus DNA loss is abolished in cells that cannot divide. We propose that in cells defective for RecBCD-mediated DSB repair the terminus region of the chromosome remains in the way of the growing septum during cell division, then septum closure triggers chromosome breakage and, in turn, DNA degradation.