scholarly journals Microhomology-mediated end-joining-dependent integration of donor DNA in cells and animals using TALENs and CRISPR/Cas9

2014 ◽  
Vol 5 (1) ◽  
Author(s):  
Shota Nakade ◽  
Takuya Tsubota ◽  
Yuto Sakane ◽  
Satoshi Kume ◽  
Naoaki Sakamoto ◽  
...  
Keyword(s):  
Genome Engineering ◽  
Cultured Cells ◽  
Human Cells ◽  
Transcription Activator ◽  
End Joining ◽  
Precise Integration ◽  
Target Chromosome ◽  
Efficient Integration ◽  
Programmable Nucleases ◽  
Plasmid Backbone

Abstract Genome engineering using programmable nucleases enables homologous recombination (HR)-mediated gene knock-in. However, the labour used to construct targeting vectors containing homology arms and difficulties in inducing HR in some cell type and organisms represent technical hurdles for the application of HR-mediated knock-in technology. Here, we introduce an alternative strategy for gene knock-in using transcription activator-like effector nucleases (TALENs) and clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated 9 (Cas9) mediated by microhomology-mediated end-joining, termed the PITCh (Precise Integration into Target Chromosome) system. TALEN-mediated PITCh, termed TAL-PITCh, enables efficient integration of exogenous donor DNA in human cells and animals, including silkworms and frogs. We further demonstrate that CRISPR/Cas9-mediated PITCh, termed CRIS-PITCh, can be applied in human cells without carrying the plasmid backbone sequence. Thus, our PITCh-ing strategies will be useful for a variety of applications, not only in cultured cells, but also in various organisms, including invertebrates and vertebrates.

scholarly journals Targeted genome editing by lentiviral protein transduction of zinc-finger and TAL-effector nucleases

eLife ◽  
2014 ◽  
Vol 3 ◽  
Author(s):  
Yujia Cai ◽  
Rasmus O Bak ◽  
Jacob Giehm Mikkelsen
Keyword(s):  
Zinc Finger ◽  
Genome Engineering ◽  
Effective Means ◽  
Zinc Finger Nucleases ◽  
Protein Transduction ◽  
Gene Correction ◽  
Transcription Activator ◽  
Homology Directed Repair ◽  
Target Locus ◽  
Programmable Nucleases

Future therapeutic use of engineered site-directed nucleases, like zinc-finger nucleases (ZFNs) and transcription activator-like effector nucleases (TALENs), relies on safe and effective means of delivering nucleases to cells. In this study, we adapt lentiviral vectors as carriers of designer nuclease proteins, providing efficient targeted gene disruption in vector-treated cell lines and primary cells. By co-packaging pairs of ZFN proteins with donor RNA in ‘all-in-one’ lentiviral particles, we co-deliver ZFN proteins and the donor template for homology-directed repair leading to targeted DNA insertion and gene correction. Comparative studies of ZFN activity in a predetermined target locus and a known nearby off-target locus demonstrate reduced off-target activity after ZFN protein transduction relative to conventional delivery approaches. Additionally, TALEN proteins are added to the repertoire of custom-designed nucleases that can be delivered by protein transduction. Altogether, our findings generate a new platform for genome engineering based on efficient and potentially safer delivery of programmable nucleases.

scholarly journals A genetically encoded inhibitor of 53BP1 to stimulate homology-based gene editing

2016 ◽  
Author(s):  
Marella D. Canny ◽  
Leo C.K. Wan ◽  
Amélie Fradet-Turcotte ◽  
Alexandre Orthwein ◽  
Nathalie Moatti ◽  
...  
Keyword(s):  
Genome Editing ◽  
Genome Engineering ◽  
Cell Types ◽  
Strand Break ◽  
End Joining ◽  
Dsb Repair ◽  
Non Homologous End Joining ◽  
G1 Cells ◽  
Programmable Nucleases ◽  
End Resection

AbstractThe expanding repertoire of programmable nucleases such as Cas9 brings new opportunities in genetic medicine1–3. In many cases, these nucleases are engineered to induce a DNA double-strand break (DSB) to stimulate precise genome editing by homologous recombination (HR). However, HR efficiency is nearly always hindered by competing DSB repair pathways such as non-homologous end-joining (NHEJ). HR is also profoundly suppressed in non-replicating cells, thus precluding the use of homology-based genome engineering in a wide variety4 of cell types. Here, we report the development of a genetically encoded inhibitor of 53BP1 (known as TP53BP1), a regulator of DSB repair pathway choice5. 53BP1 promotes NHEJ over HR by suppressing end resection, the formation of 3-prime single-stranded DNA tails, which is the rate-limiting step in HR initiation. 53BP1 also blocks the recruitment of the HR factor BRCA1 to DSB sites in G1 cells4,6. The inhibitor of 53BP1 (or i53) was identified through the screening of a massive combinatorial library of engineered ubiquitin variants by phage display7. i53 binds and occludes the ligand binding site of the 53BP1 Tudor domain with high affinity and selectivity, blocking its ability to accumulate at sites of DNA damage. i53 is a potent selective inhibitor of 53BP1 and enhances gene targeting and chromosomal gene conversion, two HR-dependent reactions. Finally, i53 can also activate HR in G1 cells when combined with the activation of end-resection and KEAP1 inhibition. We conclude that 53BP1 inhibition is a robust tool to enhance precise genome editing by canonical HR pathways.

Prime-editors (nickases), hRad51–Cas9 nickase fusions and dCas9 have the same problem as conventional CRISPR-Cas9 of plasmid/Cas9 integration after making a double stranded break

2019 ◽  
Author(s):  
Sandeep Chakraborty
Keyword(s):  
Cellular Response ◽  
Sequencing Data ◽  
Dna Breaks ◽  
Precise Integration ◽  
Guide Rna ◽  
Double Strand Dna Breaks ◽  
Human Therapy ◽  
P53 Activation ◽  
Programmable Nucleases

‘Prime-editing’ proposes to replace traditional programmable nucleases (CRISPR-Cas9) using a catalytically impaired Cas9 (dCas9) connected to a engineered reverse transcriptase, and a guide RNA encoding both the target site and the desired change. With just a ‘nick’ on one strand, it is hypothe- sized, the negative, uncontrollable effects arising from double-strand DNA breaks (DSBs) - translocations, complex proteins, integrations and p53 activation - will be eliminated. However, sequencing data pro- vided (Accid:PRJNA565979) reveal plasmid integration, indicating that DSBs occur. Also, looking at only 16 off-targets is inadequate to assert that Prime-editing is more precise. Integration of plasmid occurs in all three versions (PE1/2/3). Interestingly, dCas9 which is known to be toxic in E. coli and yeast, is shown to have residual endonuclease activity. This also affects studies that use dCas9, like base- editors and de/methylations systems. Previous work using hRad51–Cas9 nickases also show significant integration in on-targets, as well as off-target integration [1]. Thus, we show that cellular response to nicking involves DSBs, and subsequent plasmid/Cas9 integration. This is an unacceptable outcome for any in vivo application in human therapy.

scholarly journals Inactivation of Hepatitis B Virus Replication in Cultured Cells and In Vivo with Engineered Transcription Activator-Like Effector Nucleases

2013 ◽  
Vol 21 (10) ◽  
pp. 1889-1897 ◽  
Author(s):  
Kristie Bloom ◽  
Abdullah Ely ◽  
Claudio Mussolino ◽  
Toni Cathomen ◽  
Patrick Arbuthnot
Keyword(s):  
Hepatitis B Virus ◽  
Hepatitis B ◽  
Virus Replication ◽  
Cultured Cells ◽  
Transcription Activator ◽  
B Virus

scholarly journals Revised subunit order of mammalian septin complexes explains their in-vitro polymerization properties

2020 ◽  
pp. mbc.E20-06-0398
Author(s):  
Forooz Soroor ◽  
Moshe S. Kim ◽  
Oliva Palander ◽  
Yadu Balachandran ◽  
Richard F. Collins ◽  
...  
Keyword(s):  
Human Cells ◽  
Cytoskeletal Proteins ◽  
End Joining ◽  
Gtp Binding ◽  
Specific Composition ◽  
End To End ◽  
And Behavior ◽  
Filament Type

Septins are conserved GTP-binding cytoskeletal proteins that polymerize into filaments by end-to-end joining of heterooligomeric complexes. In human cells, both hexamers and octamers exist, and crystallography studies predicted the order of the hexamers to be SEPT7-SEPT6-SEPT2-SEPT2-SEPT6-SEPT7, while octamers are thought to have the same core, but with SEPT9 at the ends. However, based on this septin organization, octamers and hexamers would not be expected to co-polymerize due to incompatible ends. Here we isolated hexamers and octamers of specific composition from human cells and show that hexamers and octamers polymerize individually and, surprisingly, with each other. Binding of the BD3 domain of Borg3 results in distinctive clustering of each filament type. Moreover, we show that the organization of hexameric and octameric complexes is inverted compared to its original prediction. This revised septin organization is congruent with the organization and behavior of yeast septins suggesting that their properties are more conserved than was previously thought.

scholarly journals TALEN and CRISPR/Cas Genome Editing Systems: Tools of Discovery

Acta Naturae ◽  
2014 ◽  
Vol 6 (3) ◽  
pp. 19-40 ◽  
Author(s):  
A. A. Nemudryi ◽  
K. R. Valetdinova ◽  
S. P. Medvedev ◽  
S. M. Zakian
Keyword(s):  
Genome Editing ◽  
Dna Sequences ◽  
Genome Engineering ◽  
Disease Modeling ◽  
Regulation Of Gene Expression ◽  
Hereditary Disease ◽  
Transcription Activator ◽  
Wide Range ◽  
High Standards ◽  
Phenotype Formation

Precise studies of plant, animal and human genomes enable remarkable opportunities of obtained data application in biotechnology and medicine. However, knowing nucleotide sequences isnt enough for understanding of particular genomic elements functional relationship and their role in phenotype formation and disease pathogenesis. In post-genomic era methods allowing genomic DNA sequences manipulation, visualization and regulation of gene expression are rapidly evolving. Though, there are few methods, that meet high standards of efficiency, safety and accessibility for a wide range of researchers. In 2011 and 2013 novel methods of genome editing appeared - this are TALEN (Transcription Activator-Like Effector Nucleases) and CRISPR (Clustered Regulatory Interspaced Short Palindromic Repeats)/Cas9 systems. Although TALEN and CRISPR/Cas9 appeared recently, these systems have proved to be effective and reliable tools for genome engineering. Here we generally review application of these systems for genome editing in conventional model objects of current biology, functional genome screening, cell-based human hereditary disease modeling, epigenome studies and visualization of cellular processes. Additionally, we review general strategies for designing TALEN and CRISPR/Cas9 and analyzing their activity. We also discuss some obstacles researcher can face using these genome editing tools.

scholarly journals Efficient genome engineering by targeted homologous recombination in mouse embryos using transcription activator-like effector nucleases

2014 ◽  
Vol 5 (1) ◽  
Author(s):  
Daniel Sommer ◽  
Annika E. Peters ◽  
Tristan Wirtz ◽  
Maren Mai ◽  
Justus Ackermann ◽  
...  
Keyword(s):  
Homologous Recombination ◽  
Genome Engineering ◽  
Mouse Embryos ◽  
Transcription Activator

scholarly journals Mutagenesis and Genome Engineering of Epstein–Barr Virus in Cultured Human Cells by CRISPR/Cas9

2016 ◽  
pp. 23-31 ◽  
Author(s):  
Kit-San Yuen ◽  
Chi-Ping Chan ◽  
Kin-Hang Kok ◽  
Dong-Yan Jin
Keyword(s):  
Epstein Barr Virus ◽  
Genome Engineering ◽  
Human Cells ◽  
Barr Virus ◽  
Cultured Human Cells ◽  
Epstein Barr

Double strand break (DSB) repair pathways in plants and their application in genome engineering

2021 ◽  
pp. 27-62
Author(s):  
Natalja Beying ◽  
◽  
Carla Schmidt ◽  
Holger Puchta ◽  
◽  
...  
Keyword(s):  
Genome Engineering ◽  
Plant Cells ◽  
Strand Break ◽  
End Joining ◽  
Dsb Repair ◽  
Strand Breaks ◽  
Repair Mechanisms ◽  
Repair Pathways ◽  
Non Homologous End Joining ◽  
Underlying Mechanisms

In genome engineering, after targeted induction of double strand breaks (DSBs) researchers take advantage of the organisms’ own repair mechanisms to induce different kinds of sequence changes into the genome. Therefore, understanding of the underlying mechanisms is essential. This chapter will review in detail the two main pathways of DSB repair in plant cells, non-homologous end joining (NHEJ) and homologous recombination (HR) and sum up what we have learned over the last decades about them. We summarize the different models that have been proposed and set these into relation with the molecular outcomes of different classes of DSB repair. Moreover, we describe the factors that have been identified to be involved in these pathways. Applying this knowledge of DSB repair should help us to improve the efficiency of different types of genome engineering in plants.

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