The T4 phage DNA mimic protein Arn inhibits the DNA binding activity of the bacterial histone-like protein H-NS.
Ontology highlight
ABSTRACT:
SUBMITTER: Ho CH
PROVIDER: S-EPMC4175342 | biostudies-literature | 2014 Sep
REPOSITORIES: biostudies-literature
Similar Datasets
Project description:Purpose: To investigated the role of MotB in T4 infections Method: NapIV NS were grown to a cell density of ~4 x 10^8 cells/mL (OD600 ~0.4) then infected with either wild-type T4D+ or T4motBam at a MOI of 10. RNA was isolated at 5 post-infection using method II of (Hinton 1989). rRNA subtraction was performed with the bacterial RiboMinus Kit (Ambion) according to manufacturer instructions. cDNA was prepared using the NEBNext strand specific kit (New England BioLabs) according to manufacturer instruction for libraries with 300-450 bp insert size with the following modifications. Illumina adaptors sequences based on TruSeq HT Sample Prep Kits were purchase from Integrated DNA Technologies and used in the ligation step. TruSeq-1 and TruSeq-2 primer were used for PCR enrichment of adaptor ligated DNA. Library size was verified with a Bioanalyzer using an Agilent High Sensitivity DNA kit. The concentration of each library was determined using the KAPA Library Quantification Kit for Illumina platforms. Sequencing was performed by the NIDDK Genomics Core facility using a MiSeq system with the MiSeq 2 x 250 bp Sequencing Kit (Illumina). Result: RNA-seq data revealed that the expression of only six late genes, which decreased from 2 to 4.8-fold, were significantly affected in the T4motBam infection relative to T4 wt at 5 min after infection. The expression of early and middle genes did not change. Conclusion: MotB is a bactericidal DNA-binding protein that improves the fitness of T4 infections.
2018-04-21 | GSE113425 | GEO
Project description:The lytic bacteriophage T4 employs multiple phage-encoded early proteins to takeover the Escherichia coli host. However, the functions of many of these proteins are not known. In this study, we have characterized the T4 early gene motB, located in a dispensable region of the T4 genome. We show that heterologous production of MotB is highly toxic to E. coli, resulting in cell death or growth arrest depending on the strain and that the presence of motB increases T4 burst size 2-fold. Previous work suggested that motB affects middle gene expression, but our transcriptome analyses of T4 motBam vs. T4 wt infections reveal that only a few late genes are mildly impaired at 5 min post-infection, and expression of early and middle genes is unaffected. We find that MotB is a DNA-binding protein that binds both unmodified host and T4 modified [(glucosylated, hydroxymethylated-5 cytosine, (GHme-C)] DNA with no detectable sequence specificity. Interestingly, MotB copurifies with the host histone-like proteins, H-NS and StpA, either directly or through cobinding to DNA. We show that H-NS also binds modified T4 DNA and speculate that MotB may alter how H-NS interacts with T4 DNA, host DNA, or both, thereby improving the growth of the phage.
| S-EPMC6070864 | biostudies-literature
Project description:BackgroundMicrobial mutagenesis is an important avenue to acquire microbial strains with desirable traits for industry application. However, mutagens either chemical or physical used often leads narrow library pool due to high lethal rate. The T4 DNA ligase is one of the most widely utilized enzymes in modern molecular biology. Its contribution to repair chromosomal DNA damages, therefore cell survival during mutagenesis will be discussed.ResultsExpression of T4 DNA ligase in vivo could substantially increase cell survival to ionizing radiation in multiple species. A T4 mediated survival-coupled mutagenesis approach was proposed. When polyhydroxybutyrate (PHB)-producing E. coli with T4 DNA ligase expressed in vivo was subjected to ionizing radiation, mutants with improved PHB production were acquired quickly owing to a large viable mutant library generated. Draft genome sequence analysis showed that the mutants obtained possess not only single nucleotide variation (SNV) but also DNA fragment deletion, indicating that T4 DNA ligase in vivo may contribute to the repair of DNA double strand breaks.ConclusionsExpression of T4 DNA ligase in vivo could notably enhance microbial survival to excess chromosomal damages caused by various mutagens. Potential application of T4 DNA ligase in microbial mutagenesis was explored by mutating and screening PHB producing E. coli XLPHB strain. When applied to atmospheric and room temperature plasma (ARTP) microbial mutagenesis, large survival pool was obtained. Mutants available for subsequent screening for desirable features. The use of T4 DNA ligase we were able to quickly improve the PHB production by generating a larger viable mutants pool. This method is a universal strategy can be employed in wide range of bacteria. It indicated that traditional random mutagenesis became more powerful in combine with modern genetic molecular biology and has exciting prospect.
| S-EPMC6567493 | biostudies-literature
Project description:Nucleoid Associated Proteins (NAPs) organize the bacterial chromosome within the nucleoid. The interaction of the NAP H-NS with DNA also represses specific host and xenogeneic genes. Previously, we showed that the bacteriophage T4 early protein MotB binds to DNA, co-purifies with H-NS/DNA, and improves phage fitness. Here we demonstrate using atomic force microscopy that MotB compacts the DNA with multiple MotB proteins at the center of the complex. These complexes differ from those observed with H-NS and other NAPs, but resemble those formed by the NAP-like proteins CbpA/Dps and yeast condensin. Fluorescent microscopy indicates that expression of motB in vivo, at levels like that during T4 infection, yields a significantly compacted nucleoid containing MotB and H-NS. motB overexpression dysregulates hundreds of host genes; ∼70% are within the hns regulon. In infected cells overexpressing motB, 33 T4 late genes are expressed early, and the T4 early gene repEB, involved in replication initiation, is up ∼5-fold. We postulate that MotB represents a phage-encoded NAP that aids infection in a previously unrecognized way. We speculate that MotB-induced compaction may generate more room for T4 replication/assembly and/or leads to beneficial global changes in host gene expression, including derepression of much of the hns regulon.
| S-EPMC8450097 | biostudies-literature
Project description:Purpose: We investigated the effect of the T4 MotB protein on E. coli gene expression Method: BL21(DE3) E. coli containing either pNW129 or pNW129-MotB were grown to early log phase (OD600 ~ 0.3) then induced with 0.2% arabinose for 20 minutes. Cells were then harvested and total RNA was isolated. The cDNA library was prepared using a modified RNATagSeq workflow as previously described (Shishkin, A.A. et al. 2015 Nat Methods). Optimum fragmentation of the total RNA samples in this library was determined to be 3 min at 94C in FastAP buffer (Thermo Fischer Scientific). The cDNA Library was run on a Bioanalyzer using the Agilent High Sensitivity DNA Kit to evaluate the quality of the library. The concentration of the cDNA library was determined by qPCR using the KAPA Library Quantification Kit (Kapa Biosystems, Wilmington, MA, USA) and CFX96 Real-Time PCR Detection System (Bio-Rad, Hercules, CA, USA). Sequencing was performed by the NIDDK Genomics Core facility using a MiSeq system with the single-end 50 bp Sequencing Kit (Illumina, San Diego, CA, USA). RNA-seq data was processed as previously described using E. coli B str. DE3 (NC_012971.2) as the reference genome. Differential expression between conditions was represented as a fold change, and genes with both a fold change ≥2 and adjusted p value ≤ 0.05 were considered significant. Results: RNA-seq data revealed that the expression of genes encoded in the cryptic prograge Lambda DE3 as well as an additional 29 of E. coli genes were significantly increased after motB expression. Conclusion: T4 MotB is a DNA binding protein that compacts host DNA and disrupts H-NS dependent repression.
2020-06-11 | GSE152170 | GEO
Project description:Genetic studies have established that lysis inhibition in bacteriophage T4 infections occurs when the RI antiholin inhibits the lethal hole-forming function of the T holin. The T-holin is composed of a single N-terminal transmembrane domain and a ~20 kDa periplasmic domain. It accumulates harmlessly throughout the bacteriophage infection cycle until suddenly causing permeabilization of the inner membrane, thereby initiating lysis. The RI antiholin has a SAR domain that directs its secretion to the periplasm, where it can either be inactivated and degraded or be activated as a specific inhibitor of T. Previously, it was shown that the interaction of the soluble domains of these two proteins within the periplasm was necessary for lysis inhibition. We have purified and characterized the periplasmic domains of both T and RI. Both proteins were purified in a modified host that allows disulfide bond formation in the cytoplasm, due to the functional requirement of conserved disulfide bonds. Analytical centrifugation and circular dichroism spectroscopy showed that RI was monomeric and exhibited ~80% alpha-helical content. In contrast, T exhibited a propensity to oligomerize and precipitate at high concentrations. Incubation of RI with T inhibits this aggregation and results in a complex of equimolar T and RI content. Although gel filtration analysis indicated a complex mass of 45 kDa, intermediate between the predicted 30 kDa heterodimer and 60 kDa heterotetramer, sedimentation velocity analysis indicated that the predominant species is the former. These results suggest that RI binding to T is necessary and sufficient for lysis inhibition.
| S-EPMC3375757 | biostudies-literature
Project description:The 5.5 protein (T7p32) of coliphage T7 (5.5(T7)) was shown to bind and inhibit gene silencing by the nucleoid-associated protein H-NS, but the mechanism by which it acts was not understood. The 5.5(T7) protein is insoluble when expressed in Escherichia coli, but we find that 5.5(T7) can be isolated in a soluble form when coexpressed with a truncated version of H-NS followed by subsequent disruption of the complex during anion-exchange chromatography. Association studies reveal that 5.5(T7) binds a region of H-NS (residues 60 to 80) recently found to contain a distinct domain necessary for higher-order H-NS oligomerization. Accordingly, we find that purified 5.5(T7) can disrupt higher-order H-NS-DNA complexes in vitro but does not abolish DNA binding by H-NS per se. Homologues of the 5.5(T7) protein are found exclusively among members of the Autographivirinae that infect enteric bacteria, and despite fairly low sequence conservation, the H-NS binding properties of these proteins are largely conserved. Unexpectedly, we find that the 5.5(T7) protein copurifies with heterogeneous low-molecular-weight RNA, likely tRNA, through several chromatography steps and that this interaction does not require the DNA binding domain of H-NS. The 5.5 proteins utilize a previously undescribed mechanism of H-NS antagonism that further highlights the critical importance that higher-order oligomerization plays in H-NS-mediated gene repression.
| S-EPMC3165711 | biostudies-literature
Project description:BREX (for BacteRiophage EXclusion) is a superfamily of common bacterial and archaeal defence systems active against diverse bacteriophages. While the mechanism of BREX defence is currently unknown, self versus non-self differentiation requires methylation of specific asymmetric sites in host DNA by BrxX (PglX) methyltransferase. Here, we report that T7 bacteriophage Ocr, a DNA mimic protein that protects the phage from the defensive action of type I restriction-modification systems, is also active against BREX. In contrast to the wild-type phage, which is resistant to BREX defence, T7 lacking Ocr is strongly inhibited by BREX, and its ability to overcome the defence could be complemented by Ocr provided in trans. We further show that Ocr physically associates with BrxX methyltransferase. Although BREX+ cells overproducing Ocr have partially methylated BREX sites, their viability is unaffected. The result suggests that, similar to its action against type I R-M systems, Ocr associates with as yet unidentified BREX system complexes containing BrxX and neutralizes their ability to both methylate and exclude incoming phage DNA.
| S-EPMC7261183 | biostudies-literature
Project description:DNA double-strand breaks (DSBs) are one of the most lethal forms of DNA damage that is not efficiently repaired in prokaryotes. Certain microorganisms can handle chromosomal DSBs using the error-prone non-homologous end joining (NHEJ) system and ultimately cause genome mutagenesis. Here, we demonstrated that Enterobacteria phage T4 DNA ligase alone is capable of mediating in vivo chromosome DSBs repair in Escherichia coli. The ligation efficiency of DSBs with T4 DNA ligase is one order of magnitude higher than the NHEJ system from Mycobacterium tuberculosis. This process introduces chromosome DNA excision with different sizes, which can be manipulated by regulating the activity of host-exonuclease RecBCD. The DNA deletion length reduced either by inactivating recB or expressing the RecBCD inhibitor Gam protein from λ phage. Furthermore, we also found single nucleotide substitutions at the DNA junction, suggesting that T4 DNA ligase, as a single component non-homologous end joining system, has great potential in genome mutagenesis, genome reduction and genome editing.
| S-EPMC6525309 | biostudies-literature
Project description:Uracil-DNA glycosylase (UDG) is a key repair enzyme responsible for removing uracil residues from DNA. Interestingly, UDG is the only enzyme known to be inhibited by two different DNA mimic proteins: p56 encoded by the Bacillus subtilis phage 29 and the well-characterized protein Ugi encoded by the B. subtilis phage PBS1/PBS2. Atomic-resolution crystal structures of the B. subtilis UDG both free and in complex with p56, combined with site-directed mutagenesis analysis, allowed us to identify the key amino acid residues required for enzyme activity, DNA binding and complex formation. An important requirement for complex formation is the recognition carried out by p56 of the protruding Phe191 residue from B. subtilis UDG, whose side-chain is inserted into the DNA minor groove to replace the flipped-out uracil. A comparative analysis of both p56 and Ugi inhibitors enabled us to identify their common and distinctive features. Thereby, our results provide an insight into how two DNA mimic proteins with different structural and biochemical properties are able to specifically block the DNA-binding domain of the same enzyme.
| S-EPMC3711442 | biostudies-literature