Project description:Counting DNA reads using whole genome sequencing is providing new insight into DNA double-strand break repair (DSBR) in the model organism Escherichia coli. We describe the application of RecA chromatin immunoprecipitation coupled to genomic DNA sequencing (RecA-ChIP-seq) and marker frequency analysis (MFA) to analyse the genomic consequences of DSBR.
Project description:Counting DNA reads using whole genome sequencing is providing new insight into DNA double-strand break repair (DSBR) in the model organism Escherichia coli. We describe the application of RecA chromatin immunoprecipitation coupled to genomic DNA sequencing (RecA-ChIP-seq) and marker frequency analysis (MFA) to analyse the genomic consequences of DSBR.
Project description:We used whole bodies of four different adult fire ant morphs (alate queens, workers, haploid males, and diploid males) from a single polygyne colony to generate single-base resolution DNA methylation maps. DNA was extracted from whole bodies of individual males, individual queens, and pooled workers. Bisulfite conversion and sequencing was performed by Beijing Genomics Institute (Shenzhen, China). Unmethylated enterobacteria phage lambda DNA (GenBank accession: J02459.1) was added to each genomic DNA sample as a control for bisulfite conversion efficiency.
Project description:Restriction-modification (R-M) systems protect against phage infection by detecting and degrading invading foreign DNA. However, like many prokaryotic anti-phage defenses, R-M systems pose a significant risk of auto-immunity, exacerbated by the presence of hundreds to thousands of potential cleavage sites in the bacterial genome. Pseudomonas aeruginosa strains experience the temporary inactivation of restriction endonucleases (tiREN) upon growth at high temperatures, but the mechanisms and implications of this are unknown. Here, we report that P. aeruginosa Type I restriction endonuclease (HsdR) is degraded, and the methyltransferase (HsdMS) is partially degraded, by two Lon-like proteases when replicating above 41 °C. This post-translational regulation prevents self-DNA targeting and leads to partial genomic hypomethylation, as demonstrated by SMRT sequencing and eTAM-seq. Interestingly, upon return to 37 ºC, restriction activity and full genomic methylation do not fully recover for up to 60 bacterial generations. Our findings demonstrate that Type I R-M is tightly regulated post-translationally with a long memory effect that ensures genomic stability and mitigates auto-toxicity.
Project description:The CpG depleted Mycoplasma penetrans harbors a CpG specific C5 methyltransferase. The aim of this experiment was to confirm the specificity of the methyltransferase in vivo and in vitro. Genomic DNA from Mycoplasma penetrans and Escherichia coli genomic DNA that either was or was not methylated in vitro by M.MpeI were subjected to Illumina MiSeq bisulfite sequencing.
Project description:Pseudomonas virus PA5oct has a large, linear, double-stranded DNA genome (286,783 bp) and is related to Escherichia phages 121Q/PBECO 4, Klebsiella phage vB_KleM-RaK2, Klebsiella phage K64-1, and Cronobacter phage vB_CsaM_GAP32. A protein-sharing network analysis highlights the conserved core genes within this clade. Combining hybrid genome sequencing, RNA-Seq and mass spectrometry analyses of its virion proteins allowed us to accurately identify genes and elucidate regulatory elements for this phage (ncRNAs, tRNAs and promoter elements). In total PA5oct encodes 449 CDS of which 93, have been identified as virion-associated based on ESI-MS/MS. The RNA-Seq-based temporal genome organization suggests a gradual take-over by viral transcripts from 21%, 69%, and 93% at 5, 15 and 25 min after infection, respectively . Like many large phages, PA5oct is not organized into contiguous regions of temporal transcription. However, although the temporal regulation of the PA5oct genome expression reveals specific genome clusters expressed in early and late infection, many genes encoding experimentally observed structural proteins surprisingly appear to remain almost untranscribed throughout the infection cycle. Within the host, operons associated with elements of a cryptic Pf1-like prophage are upregulated, as are operons responsible for Psl exopolysaccharide (pslE-J) and periplasmic nitrate reductase (napA-F) production. The characterization described here represents a crucial step towards understanding the genomic complexity as well as molecular diversity of jumbo viruses.