CRISPR-Cas systems are bacterial anti-viral systems, and bacterial viruses (bacteriophages, phages) can carry anti-CRISPR (Acr) proteins to evade that immunity. Acrs can also fine-tune the activity of CRISPR-based genome-editing tools. While Acrs are prevalent in phages capable of lying dormant in a CRISPR-carrying host, their orthologs have been observed only infrequently in virulent phages. Here we identify AcrIIA6, an Acr encoded in 33% of virulent Streptococcus thermophilus phage genomes. The X-ray structure of AcrIIA6 displays some features unique to this Acr family. We compare the activity of AcrIIA6 to those of other Acrs, including AcrIIA5 (also from S. thermophilus phages), and characterize their effectiveness against a range of CRISPR-Cas systems. Finally, we demonstrate that both Acr families from S. thermophilus phages inhibit Cas9-mediated genome editing of human cells.
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http://dx.doi.org/10.1038/s41467-018-05092-w | DOI Listing |
Nat Commun
December 2024
Department of Chemical and Biomolecular Engineering, Rice University, Houston, TX, USA.
Programmable and modular systems capable of orthogonal genomic and transcriptomic perturbations are crucial for biological research and treating human genetic diseases. Here, we present the minimal versatile genetic perturbation technology (mvGPT), a flexible toolkit designed for simultaneous and orthogonal gene editing, activation, and repression in human cells. The mvGPT combines an engineered compact prime editor (PE), a fusion activator MS2-p65-HSF1 (MPH), and a drive-and-process multiplex array that produces RNAs tailored to different types of genetic perturbation.
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December 2024
Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, Japan.
The CRISPR-associated endonuclease Cas9 derived from prokaryotes is used as a genome editing, which targets specific genomic loci by single guide RNAs (sgRNAs). The eukaryotes, the target of genome editing, store their genome DNA in chromatin, in which the nucleosome is a basic unit. Despite previous structural analyses focusing on Cas9 cleaving free DNA, structural insights into Cas9 targeting of DNA within nucleosomes are limited, leading to uncertainties in understanding how Cas9 operates in the eukaryotic genome.
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December 2024
The SKI Stem Cell Research Facility, The Center for Stem Cell Biology and Developmental Biology Program, Sloan-Kettering Institute for Cancer Research, 1275 York Avenue, New York, NY, USA.
Prime editing (PE) allows for precise genome editing in human pluripotent stem cells (hPSCs), such as introducing single nucleotide modifications, small insertions or deletions at a specific genomic locus. Here, we systematically compare a panel of prime editing conditions in hPSCs and generate a potent prime editor, "PE-Plus", through co-inhibition of mismatch repair and p53-mediated cellular stress responses. We further establish an inducible prime editing platform in hPSCs by incorporating the PE-Plus into a safe-harbor locus and demonstrated temporal control of precise editing in both hPSCs and differentiated cells.
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December 2024
Beijing Frontier Research Center for Biological Structure, State Key Laboratory of Membrane Biology, School of Life Sciences, Tsinghua University, Beijing, 100084, China.
Exceptionally diverse type V CRISPR-Cas systems provide numerous RNA-guided nucleases as powerful tools for DNA manipulation. Two known Cas12e nucleases, DpbCas12e and PlmCas12e, are both effective in genome editing. However, many differences exist in their in vitro dsDNA cleavage activities, reflecting the diversity in Cas12e's enzymatic properties.
View Article and Find Full Text PDFMicrob Cell Fact
December 2024
Department of Chemical Engineering, University of Waterloo, Waterloo, Canada.
Background: Pseudomonas putida KT2440, a non-pathogenic soil bacterium, is a key platform strain in synthetic biology and industrial applications due to its robustness and metabolic versatility. Various systems have been developed for genome editing in P. putida, including transposon modules, integrative plasmids, recombineering systems, and CRISPR/Cas systems.
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