Publications by authors named "Moran G Goren"

The evolutionary arms race between bacteria and phages led to the emergence of bacterial immune systems whose diversity and dynamics remain poorly understood. Here we use comparative genomics to describe a widespread genetic element, defined by the presence of the Gamma-Mobile-Trio (GMT) proteins, that serves as a reservoir of offensive and defensive tools. We demonstrate, using Vibrio parahaemolyticus as a model, that GMT-containing genomic islands are active mobile elements.

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Article Synopsis
  • - Scientists are exploring the use of CRISPR-Cas systems as targeted antimicrobials against bacterial infections, particularly focusing on multidrug-resistant strains of Klebsiella pneumoniae.
  • - The study found that DNA-targeting Cas nucleases were more effective than RNA-targeting ones, with AsCas12a showing promising results, although different guide RNAs had varying effectiveness based on strain-specific factors.
  • - A genome-wide screen identified design rules for guide RNAs and helped develop an algorithm to predict their efficiency, ultimately demonstrating that Cas12a can be used in phagemids to eliminate K. pneumoniae.
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We have identified a novel phage-encoded inhibitor of the major cytoskeletal protein in bacterial division, FtsZ. The inhibition is shown to confer T5 bacteriophage with a growth advantage in dividing hosts. Our studies demonstrate a strategy in bacteriophages to maximize their progeny number by inhibiting escape of one of the daughter cells of an infected bacterium.

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Most recently developed phage engineering technologies are based on the CRISPR-Cas system. Here, we present a non-CRISPR-based method for genetically engineering the phages T5, T7, P1, and λ by adapting the pORTMAGE technology, which was developed for engineering bacterial genomes. The technology comprises harbouring a plasmid encoding a potent recombinase and a gene transiently silencing a repair system.

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Natural prokaryotic defense via the CRISPR-Cas system requires spacer integration into the CRISPR array in a process called adaptation. To search for adaptation proteins with enhanced capabilities, we established a robust perpetual DNA packaging and transfer (PeDPaT) system that uses a strain of T7 phage to package plasmids and transfer them without killing the host, and then uses a different strain of T7 phage to repeat the cycle. We used PeDPaT to identify better adaptation proteins-Cas1 and Cas2-by enriching mutants that provide higher adaptation efficiency.

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Bacteriophages (phages) have evolved efficient means to take over the machinery of the bacterial host. The molecular tools at their disposal may be applied to manipulate bacteria and to divert molecular pathways at will. Here, we describe a bacterial growth inhibitor, gene product T5.

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A major limitation in using bacteriophage-based applications is their narrow host range. Approaches for extending the host range have focused primarily on lytic phages in hosts supporting their propagation rather than approaches for extending the ability of DNA transduction into phage-restrictive hosts. To extend the host range of T7 phage for DNA transduction, we have designed hybrid particles displaying various phage tail/tail fiber proteins.

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Infection of Escherichia coli by the T7 phage leads to rapid and selective inhibition of the bacterial RNA polymerase (RNAP) by the 7 kDa T7 protein Gp2. We describe the identification and functional and structural characterisation of a novel 7 kDa T7 protein, Gp5.7, which adopts a winged helix-turn-helix-like structure and specifically represses transcription initiation from host RNAP-dependent promoters on the phage genome via a mechanism that involves interaction with DNA and the bacterial RNAP.

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Prokaryotic adaptive immune systems are composed of clustered regularly interspaced short palindromic repeats (CRISPR) and CRISPR-associated (Cas) proteins. These systems adapt to new threats by integrating short nucleic acids, termed spacers, into the CRISPR array. The functional motifs in the repeat and the mechanism by which a constant repeat size is maintained are still elusive.

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Bacteriophages, bacteria's natural enemies, may serve as potent antibacterial agents. Their specificity for certain bacterial sub-species limits their effectiveness, but allows selective targeting of bacteria. Lu and colleagues present a platform for such targeting through alteration of bacteriophages' host specificity by swapping specificity domains in their host-recognition ligand.

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The clustered regularly interspaced short palindromic repeats (CRISPR) and CRISPR associated proteins (Cas) comprise a prokaryotic adaptive defense system against foreign nucleic acids. This defense is mediated by Cas proteins, which are guided by sequences flanked by the repeats, called spacers, to target nucleic acids. Spacers designed against the prokaryotic self chromosome are lethal to the prokaryotic cell.

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CRISPR-Cas (clustered, regularly interspaced short palindromic repeats coupled with CRISPR-associated proteins) is a bacterial immunity system that protects against invading phages or plasmids. In the process of CRISPR adaptation, short pieces of DNA ('spacers') are acquired from foreign elements and integrated into the CRISPR array. So far, it has remained a mystery how spacers are preferentially acquired from the foreign DNA while the self chromosome is avoided.

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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'.

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Clustered regularly interspaced short palindromic repeats (CRISPR) and their associated proteins constitute a recently identified prokaryotic defense system against invading nucleic acids. DNA segments, termed protospacers, are integrated into the CRISPR array in a process called adaptation. Here, we establish a PCR-based assay that enables evaluating the adaptation efficiency of specific spacers into the type I-E Escherichia coli CRISPR array.

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We analyzed sequences of newly inserted repeats in an Escherichia coli CRISPR (clustered regularly interspaced short palindromic repeats) array in vivo and showed that a base previously thought to belong to the repeat is actually derived from a protospacer. Based on further experimental results, we propose to use the term "duplicon" for a repeated sequence in a CRISPR array that serves as a template for a new duplicon. Our findings suggest the possibility of redrawing the borders between repeats, spacers, and protospacer adjacent motifs.

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The clustered regularly interspaced short palindromic repeats and their associated proteins (CRISPR/Cas) constitute a recently identified prokaryotic defense mechanism against invading nucleic acids. Activity of the CRISPR/Cas system comprises of three steps: (i) insertion of alien DNA sequences into the CRISPR array to prevent future attacks, in a process called 'adaptation', (ii) expression of the relevant proteins, as well as expression and processing of the array, followed by (iii) RNA-mediated interference with the alien nucleic acid. Here we describe a robust assay in Escherichia coli to explore the hitherto least-studied process, adaptation.

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Prokaryotic DNA arrays arranged as clustered regularly interspaced short palindromic repeats (CRISPR), along with their associated proteins, provide prokaryotes with adaptive immunity by RNA-mediated targeting of alien DNA or RNA matching the sequences between the repeats. Here, we present a thorough screening system for the identification of bacterial proteins participating in immunity conferred by the Escherichia coli CRISPR system. We describe the identification of one such protein, high-temperature protein G (HtpG), a homolog of the eukaryotic chaperone heat-shock protein 90.

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Klebsiella pneumoniae carbapenemase (KPC) 3-producing Escherichia coli was isolated from a carrier of KPC-3-producing K. pneumoniae. The KPC-3 plasmid was identical in isolates of both species.

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Sporadic isolates of carbapenem-resistant KPC-2-producing Klebsiella pneumoniae were isolated in Tel Aviv Medical Center during 2005 and 2006, parallel to the emergence of the KPC-3-producing K. pneumoniae sequence type 258 (ST 258). We aimed to study the molecular epidemiology of these isolates and to characterize their bla(KPC)-carrying plasmids and their origin.

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All of the carbapenem-resistant Escherichia coli (CREC) isolates identified in our hospital from 2005 to 2008 (n = 10) were studied. CREC isolates were multidrug resistant, all carried bla(KPC-2), and six of them were also extended-spectrum beta-lactamase producers. Pulsed-field gel electrophoresis indicated six genetic clones; within the same clone, similar transferable bla(KPC-2)-containing plasmids were found whereas plasmids differed between clones.

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