CRISPR adaptation in Escherichia coli subtypeI-E system

2013 ◽  
Vol 41 (6) ◽  
pp. 1412-1415 ◽  
Author(s):  
Ruth Kiro ◽  
Moran G. Goren ◽  
Ido Yosef ◽  
Udi Qimron
Keyword(s):  
Escherichia Coli ◽  
Nucleic Acids ◽  
Present Article ◽  
Adaptation Process ◽  
Defence System ◽  
Crispr Array ◽  
Associated Proteins

The CRISPRs (clustered regularly interspaced short palindromic repeats) and their associated Cas (CRISPR-associated) proteins are a prokaryotic adaptive defence system against foreign nucleic acids. The CRISPR array comprises short repeats flanking short segments, called ‘spacers’, which are derived from foreign nucleic acids. The process of spacer insertion into the CRISPR array is termed ‘adaptation’. Adaptation allows the system to rapidly evolve against emerging threats. In the present article, we review the most recent studies on the adaptation process, and focus primarily on the subtype I-E CRISPR–Cas system of Escherichia coli.

scholarly journals CRISPR-Cas System: The Powerful Modulator of Accessory Genomes in Prokaryotes

2021 ◽  
pp. 1-16
Author(s):  
Anca Butiuc-Keul ◽  
Anca Farkas ◽  
Rahela Carpa ◽  
Dumitrana Iordache
Keyword(s):  
Nucleic Acids ◽  
Pathogenic Bacteria ◽  
The Novel ◽  
Defense System ◽  
Guide Rnas ◽  
Crispr Array ◽  
Different Types ◽  
Evolutionary Trajectories ◽  
Novel Coronavirus ◽  
Cas Proteins

Being frequently exposed to foreign nucleic acids, bacteria and archaea have developed an ingenious adaptive defense system, called CRISPR-Cas. The system is composed of the Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR) array, together with CRISPR (<i>cas</i>)-associated genes. This system consists of a complex machinery that integrates fragments of foreign nucleic acids from viruses and mobile genetic elements (MGEs), into CRISPR arrays. The inserted segments (spacers) are transcribed and then used by cas proteins as guide RNAs for recognition and inactivation of the targets. Different types and families of CRISPR-Cas systems consist of distinct adaptation and effector modules with evolutionary trajectories, partially independent. The origin of the effector modules and the mechanism of spacer integration/deletion is far less clear. A review of the most recent data regarding the structure, ecology, and evolution of CRISPR-Cas systems and their role in the modulation of accessory genomes in prokaryotes is proposed in this article. The CRISPR-Cas system&apos;s impact on the physiology and ecology of prokaryotes, modulation of horizontal gene transfer events, is also discussed here. This system gained popularity after it was proposed as a tool for plant and animal embryo editing, in cancer therapy, as antimicrobial against pathogenic bacteria, and even for combating the novel coronavirus – SARS-CoV-2; thus, the newest and promising applications are reviewed as well.

scholarly journals A Mechanism-Based Whole-Cell Screening Assay to Identify Inhibitors of Protein Export in Escherichia coli by the Sec Pathway

2012 ◽  
Vol 17 (4) ◽  
pp. 535-541 ◽  
Author(s):  
Gregory J. Crowther ◽  
S. Arshiya Quadri ◽  
Benjamin J. Shannon-Alferes ◽  
Wesley C. Van Voorhis ◽  
Henry Rosen
Keyword(s):  
Escherichia Coli ◽  
High Throughput Screening ◽  
Drug Target ◽  
Rapid Identification ◽  
Protein Synthesis Inhibitors ◽  
Screening Assay ◽  
Whole Cell ◽  
Sec Pathway ◽  
Associated Proteins ◽  
Pass Through

More than 20% of bacterial proteins are noncytoplasmic, and most of these pass through the SecYEG channel en route to the periplasm, cell membrane, or surrounding environment. The Sec pathway, encompassing SecYEG and several associated proteins (SecA, SecB, YidC, SecDFYajC), is of interest as a potential drug target because it is distinct from targets of current drugs, is essential for bacterial growth, and exhibits dissimilarities in eukaryotes and bacteria that increase the likelihood of selectively inhibiting the microbial pathway. As a step toward validating the pathway as a drug target, we have adapted a mechanism-based whole-cell assay in a manner suitable for high-throughput screening (HTS). The assay uses an engineered strain of Escherichia coli that accumulates beta-galactosidase (β-gal) in its cytoplasm if translocation through SecYEG is blocked. The assay should facilitate rapid identification of compounds that specifically block the Sec pathway because widely, toxic compounds and nonspecific protein synthesis inhibitors prevent β-gal production and thus do not register as hits. Testing of current antibiotics confirmed that they do not generally act through the Sec pathway. A mini-screen of 800 compounds indicated the assay’s readiness for larger screening projects.

scholarly journals Genomic analysis of DNA binding and gene regulation by homologous nucleoid-associated proteins IHF and HU in Escherichia coli K12

2011 ◽  
Vol 40 (8) ◽  
pp. 3524-3537 ◽  
Author(s):  
Ana I. Prieto ◽  
Christina Kahramanoglou ◽  
Ruhi M. Ali ◽  
Gillian M. Fraser ◽  
Aswin S. N. Seshasayee ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Gene Regulation ◽  
Dna Binding ◽  
Genomic Analysis ◽  
Escherichia Coli K12 ◽  
Associated Proteins

RELEASE OF ULTRAVIOLET-ABSORBING MATERIAL FROM ESCHERICHIA COLI AT SUBZERO TEMPERATURES

1963 ◽  
Vol 9 (4) ◽  
pp. 523-530 ◽  
Author(s):  
Gösta Lindeberg ◽  
Aaslaug Lode
Keyword(s):  
Escherichia Coli ◽  
Nucleic Acids ◽  
Cold Shock ◽  
Organic Phosphorus ◽  
Lethal Effect ◽  
Rapid Cooling ◽  
Pronounced Decrease ◽  
Subzero Temperatures ◽  
Absorbing Material ◽  
Freezing Seawater

When cells of Escherichia coli were suspended in dilute artificial seawater and cooled to various subzero temperatures, a maximum lethal effect occurred around −40 °C. In addition, rapid cooling to −26 °C of bacteria, suspended in concentrated, non-freezing seawater caused a pronounced decrease in viability ("cold shock"). The loss in viability was accompanied by a proportional release from the cells of ultraviolet-absorbing material and by an increase in the ribose and organic phosphorus contents of the suspending liquid. It seems possible that the released material, at least partly, consisted of nucleotides or nucleic acids.

scholarly journals Hot and crispy: CRISPR–Cas systems in the hyperthermophile Sulfolobus solfataricus

2013 ◽  
Vol 41 (6) ◽  
pp. 1422-1426 ◽  
Author(s):  
Jing Zhang ◽  
Malcolm F. White
Keyword(s):  
Present Article ◽  
Pyrococcus Furiosus ◽  
Sulfolobus Solfataricus ◽  
Host Genome ◽  
Current Understanding ◽  
Major Type ◽  
Crispr Locus ◽  
Defence System ◽  
Different Types ◽  
Foreign Dna

The CRISPR (clustered regularly interspaced short palindromic repeats) and Cas (CRISPR-associated) genes are widely spread in bacteria and archaea, representing an intracellular defence system against invading viruses and plasmids. In the system, fragments from foreign DNA are captured and integrated into the host genome at the CRISPR locus. The locus is transcribed and the resulting RNAs are processed by Cas6 into small crRNAs (CRISPR RNAs) that guide a variety of effector complexes to degrade the invading genetic elements. Many bacteria and archaea have one major type of effector complex. However, Sulfolobus solfataricus strain P2 has six CRISPR loci with two families of repeats, four cas6 genes and three different types of effector complex. These features make S. solfataricus an important model for studying CRISPR–Cas systems. In the present article, we review our current understanding of crRNA biogenesis and its effector complexes, subtype I-A and subtype III-B, in S. solfataricus. We also discuss the differences in terms of mechanisms between the subtype III-B systems in S. solfataricus and Pyrococcus furiosus.

A highly evolutionarily conserved mitochondrial protein is structurally related to the protein encoded by the Escherichia coli groEL gene

1988 ◽  
Vol 8 (1) ◽  
pp. 371-380
Author(s):  
T W McMullin ◽  
R L Hallberg
Keyword(s):  
Escherichia Coli ◽  
Tetrahymena Thermophila ◽  
Mitochondrial Protein ◽  
Cross Reactivity ◽  
Macromolecular Complexes ◽  
E Coli ◽  
Groel Gene ◽  
Evolutionarily Conserved ◽  
Associated Proteins ◽  
Related Proteins

We recently reported that a Tetrahymena thermophila 58-kilodalton (kDa) mitochondrial protein (hsp58) was selectively synthesized during heat shock. In this study, we show that hsp58 displayed antigenic similarity with mitochondrially associated proteins from Saccharomyces cerevisiae (64 kDa), Xenopus laevis (60 kDa), Zea mays (62 kDa), and human cells (59 kDa). Furthermore, a 58-kDa protein from Escherichia coli also exhibited antigenic cross-reactivity to an antiserum directed against the T. thermophila mitochondrial protein. The proteins from S. cerevisiae and E. coli antigenically related to hsp58 were studied in detail and found to share several other characteristics with hsp58, including heat inducibility and the property of associating into distinct oligomeric complexes. The T. thermophila, S. cerevisiae, and E. coli macromolecular complexes containing these related proteins had similar sedimentation characteristics and virtually identical morphologies as seen with the electron microscope. The distinctive properties of the E. coli homolog to T. thermophila hsp58 indicate that it is most likely the product of the groEL gene.

scholarly journals Heteromeric Interactions among Nucleoid-Associated Bacterial Proteins: Localization of StpA-Stabilizing Regions in H-NS of Escherichia coli

2001 ◽  
Vol 183 (7) ◽  
pp. 2343-2347 ◽  
Author(s):  
Jörgen Johansson ◽  
Sven Eriksson ◽  
Berit Sondén ◽  
Sun Nyunt Wai ◽  
Bernt Eric Uhlin
Keyword(s):  
Escherichia Coli ◽  
Stable Form ◽  
Lon Protease ◽  
Wild Type ◽  
Bacterial Proteins ◽  
Regulatory Systems ◽  
Associated Proteins ◽  
Gene Regulatory

ABSTRACT The nucleoid-associated proteins H-NS and StpA inEscherichia coli bind DNA as oligomers and are implicated in gene regulatory systems. There is evidence for both homomeric and heteromeric H-NS–StpA complexes. The two proteins show differential turnover, and StpA was previously found to be subject to protease-mediated degradation by the Lon protease. We investigated which regions of the H-NS protein are able to prevent degradation of StpA. A set of truncated H-NS derivatives was tested for their ability to mediate StpA stability and to form heteromers in vitro. The data indicate that H-NS interacts with StpA at two regions and that the presence of at least one of the H-NS regions is necessary for StpA stability. Our results also suggest that a proteolytically stable form of StpA, StpAF21C, forms dimers, whereas wild-type StpA in the absence of H-NS predominantly forms tetramers or oligomers, which are more susceptible to proteolysis.

scholarly journals Detection of spacer precursors formed in vivo during primed CRISPR adaptation

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Anna A. Shiriaeva ◽  
Ekaterina Savitskaya ◽  
Kirill A. Datsenko ◽  
Irina O. Vvedenskaya ◽  
Iana Fedorova ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Nucleic Acid ◽  
High Throughput Sequencing ◽  
Dna Degradation ◽  
Type I ◽  
Dna Fragments ◽  
Crispr Array ◽  
Foreign Dna ◽  
And Function

Abstract Type I CRISPR-Cas loci provide prokaryotes with a nucleic-acid-based adaptive immunity against foreign DNA. Immunity involves adaptation, the integration of ~30-bp DNA fragments, termed prespacers, into the CRISPR array as spacers, and interference, the targeted degradation of DNA containing a protospacer. Interference-driven DNA degradation can be coupled with primed adaptation, in which spacers are acquired from DNA surrounding the targeted protospacer. Here we develop a method for strand-specific, high-throughput sequencing of DNA fragments, FragSeq, and apply this method to identify DNA fragments accumulated in Escherichia coli cells undergoing robust primed adaptation by a type I-E or type I-F CRISPR-Cas system. The detected fragments have sequences matching spacers acquired during primed adaptation and function as spacer precursors when introduced exogenously into cells by transformation. The identified prespacers contain a characteristic asymmetrical structure that we propose is a key determinant of integration into the CRISPR array in an orientation that confers immunity.

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