scholarly journals Unusual Removal of T-DNA in T1 Progenies of Rice after Agrobacterium-mediated CRISPR/Cas9 Editing

2022 ◽  
Author(s):  
Qin Yang ◽  
Park Tae-Sung ◽  
Lee Bumkyu ◽  
Lim Myung-Ho
Keyword(s):  
Gene Editing ◽  
Gene Selection ◽  
Point Mutations ◽  
Selection Marker ◽  
Target Point ◽  
Knock Out ◽  
Right Border ◽  
Junction Site ◽  
Vector Sequences ◽  
The Right

Abstract In the present study, we attempted to knock out the bar gene selection marker in the fixed Bt- and herbicide-resistant transgenic line BT-T07 (T8 generation) to generate a marker-free Bt-resistant rice line. A binary vector containing a CRISPR/Cas9 system targeting the 108–130 bp region of bar was transformed into rice embryonic calli, and plantlets were regenerated under non-selective conditions. Three T0 plants were observed to have non-target point mutations and deletions in the targeted gene and were putatively heterozygous and chimeras. One T0 plant, 130-4, was confirmed to have a 76-nt deletion, from 140 bp to 225 bp, and it showed the segregation of bar in its T1 progenies, with 16 bar-knockout lines and seven normal bar-expressing lines. However, the CRISPR/Cas9 editing vector sequences were not detected in any of the T1 plants. In addition, unusual removal of pre-existing T-DNA was observed in all bar-knockout T1 plants. Illumina sequencing of a bar-knockout line, 130-4-36, revealed a small fraction of read residues of pre-existing T-DNA from the bar sequence to the right border at the original junction site. We speculate that this rare phenomenon might be directed by the homology between pre-existing T-DNA and CRISPR/Cas9 editing vector sequences during meiotic recombination. We report imprecise modifications and unpredictable outcomes of gene-editing techniques, providing valuable perspectives on gene-editing applications.

scholarly journals Homology-directed gene-editing approaches for hematopoietic stem and progenitor cell gene therapy

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Manoj Kumar K. Azhagiri ◽  
Prathibha Babu ◽  
Vigneshwaran Venkatesan ◽  
Saravanabhavan Thangavel
Keyword(s):  
Gene Therapy ◽  
Gene Editing ◽  
Genome Engineering ◽  
Point Mutations ◽  
Target Cells ◽  
Gene Manipulation ◽  
Hematopoietic Stem ◽  
Knock Out ◽  
Base Editing ◽  
Stem And Progenitor Cells

AbstractThe advent of next-generation genome engineering tools like CRISPR-Cas9 has transformed the field of gene therapy, rendering targeted treatment for several incurable diseases. Hematopoietic stem and progenitor cells (HSPCs) continue to be the ideal target cells for gene manipulation due to their long-term repopulation potential. Among the gene manipulation strategies such as lentiviral gene augmentation, non-homologous end joining (NHEJ)-mediated gene editing, base editing and prime editing, only the homology-directed repair (HDR)-mediated gene editing provides the option of inserting a large transgene under its endogenous promoter or any desired locus. In addition, HDR-mediated gene editing can be applied for the gene knock-out, correction of point mutations and introduction of beneficial mutations. HSPC gene therapy studies involving lentiviral vectors and NHEJ-based gene-editing studies have exhibited substantial clinical progress. However, studies involving HDR-mediated HSPC gene editing have not yet progressed to the clinical testing. This suggests the existence of unique challenges in exploiting HDR pathway for HSPC gene therapy. Our review summarizes the mechanism, recent progresses, challenges, and the scope of HDR-based gene editing for the HSPC gene therapy.

scholarly journals Knock-in and precise nucleotide substitution using near-PAMless engineered Cas9 variants in Dictyostelium discoideum

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Yuu Asano ◽  
Kensuke Yamashita ◽  
Aoi Hasegawa ◽  
Takanori Ogasawara ◽  
Hoshie Iriki ◽  
...  
Keyword(s):  
Genome Editing ◽  
Dictyostelium Discoideum ◽  
Streptococcus Pyogenes ◽  
Nucleotide Substitution ◽  
Point Mutations ◽  
Targeted Mutagenesis ◽  
Single Amino Acid ◽  
Specific Gene ◽  
Knock Out ◽  
Protospacer Adjacent Motif

AbstractThe powerful genome editing tool Streptococcus pyogenes Cas9 (SpCas9) requires the trinucleotide NGG as a protospacer adjacent motif (PAM). The PAM requirement is limitation for precise genome editing such as single amino-acid substitutions and knock-ins at specific genomic loci since it occurs in narrow editing window. Recently, SpCas9 variants (i.e., xCas9 3.7, SpCas9-NG, and SpRY) were developed that recognise the NG dinucleotide or almost any other PAM sequences in human cell lines. In this study, we evaluated these variants in Dictyostelium discoideum. In the context of targeted mutagenesis at an NG PAM site, we found that SpCas9-NG and SpRY were more efficient than xCas9 3.7. In the context of NA, NT, NG, and NC PAM sites, the editing efficiency of SpRY was approximately 60% at NR (R = A and G) but less than 22% at NY (Y = T and C). We successfully used SpRY to generate knock-ins at specific gene loci using donor DNA flanked by 60 bp homology arms. In addition, we achieved point mutations with efficiencies as high as 97.7%. This work provides tools that will significantly expand the gene loci that can be targeted for knock-out, knock-in, and precise point mutation in D. discoideum.

CRISPR–Cas9 gene editing as a tool for developing immunotherapy for cancer

2021 ◽  
Author(s):  
Moataz Dowaidar
Keyword(s):  
T Cells ◽  
Immune Cells ◽  
Peripheral Blood ◽  
Gene Editing ◽  
Genetically Engineered ◽  
Cancer Resistance ◽  
Knock Out ◽  
Tumor Tissues ◽  
Engineered T Cells ◽  
Long Time

T cells following genome editing and transformation might be detectable in peripheral blood and tumor tissues for a long time, even more than a year. The types and diversity of T-cells in peripheral blood and tumor tissues changed following transfusion of genetically modified T-cells, and some highly suspected T-cells targeting cancer cells grew, increasing the proportion of such cells. Moreover, after getting genetically engineered T cells, anticancer cytokine secretion increased. T cells changed by gene editing have certain functions, at least from an immunological standpoint. The first clinical research using the CRISPR–Cas9 gene editing method for cancer resistance is more complicated: Using CRISPR–Cas9 gene editing technology to concurrently knock out, amplify, activate and reinfuse three genes in human immune cells. This therapeutic strategy is more demanding, because the changed immune cells have a wider target scope. The data suggest that the efficacy of gene editing in immune cells was 15–45%, and the modified cells could survive long in the peripheral blood and tumor tissues of patients. After three or four months, some T-cells became central T-cells. These encouraging findings pave the way for future experimental cancer research utilizing CRISPR technology.

scholarly journals An Effective Counterselection System for Listeria monocytogenes and Its Use To Characterize the Monocin Genomic Region of Strain 10403S

2016 ◽  
Vol 83 (6) ◽  
Author(s):  
Tal Argov ◽  
Lev Rabinovich ◽  
Nadejda Sigal ◽  
Anat A. Herskovits
Keyword(s):  
Listeria Monocytogenes ◽  
Point Mutations ◽  
Model Organism ◽  
Trna Synthetase ◽  
Genomic Region ◽  
Selection Marker ◽  
Content Type ◽  
Allelic Exchange ◽  
Suicide Vector ◽  
Screening Systems

ABSTRACT Construction of Listeria monocytogenes mutants by allelic exchange has been laborious and time-consuming due to lack of proficient selection markers for the final recombination event, that is, a marker conveying substance sensitivity to the bacteria bearing it, enabling the exclusion of merodiploids and selection for plasmid loss. In order to address this issue, we engineered a counterselection marker based on a mutated phenylalanyl-tRNA synthetase gene (pheS*). This mutation renders the phenylalanine-binding site of the enzyme more promiscuous and allows the binding of the toxic p-chloro-phenylalanine analog (p-Cl-phe) as a substrate. When pheS* is introduced into L. monocytogenes and highly expressed under control of a constitutively active promoter, the bacteria become sensitive to p-Cl-phe supplemented in the medium. This enabled us to utilize pheS* as a negative selection marker and generate a novel, efficient suicide vector for allelic exchange in L. monocytogenes. We used this vector to investigate the monocin genomic region in L. monocytogenes strain 10403S by constructing deletion mutants of the region. We have found this region to be active and to cause bacterial lysis upon mitomycin C treatment. The future applications of such an effective counterselection system, which does not require any background genomic alterations, are vast, as it can be modularly used in various selection systems (e.g., genetic screens). We expect this counterselection marker to be a valuable genetic tool in research on L. monocytogenes. IMPORTANCE L. monocytogenes is an opportunistic intracellular pathogen and a widely studied model organism. An efficient counterselection marker is a long-standing need in Listeria research for improving the ability to design and perform various genetic manipulations and screening systems for different purposes. We report the construction and utilization of an efficient suicide vector for allelic exchange which can be conjugated, leaves no marker in the bacterial chromosome, and does not require the use of sometimes leaky inducible promoters. This highly efficient genome editing tool for L. monocytogenes will allow for rapid sequential mutagenesis, introduction of point mutations, and design of screening systems. We anticipate that it will be extensively used by the research community and yield novel insights into the diverse fields studied using this model organism.

scholarly journals Nonviral gene editing via CRISPR/Cas9 delivery by membrane-disruptive and endosomolytic helical polypeptide

2018 ◽  
Vol 115 (19) ◽  
pp. 4903-4908 ◽  
Author(s):  
Hong-Xia Wang ◽  
Ziyuan Song ◽  
Yeh-Hsing Lao ◽  
Xin Xu ◽  
Jing Gong ◽  
...  
Keyword(s):  
Gene Editing ◽  
Transfection Efficiency ◽  
Gene Activation ◽  
Cell Types ◽  
Biological Research ◽  
Knock Out ◽  
Safe Delivery ◽  
Pegylated Nanoparticles

Effective and safe delivery of the CRISPR/Cas9 gene-editing elements remains a challenge. Here we report the development of PEGylated nanoparticles (named P-HNPs) based on the cationic α-helical polypeptide poly(γ-4-((2-(piperidin-1-yl)ethyl)aminomethyl)benzyl-l-glutamate) for the delivery of Cas9 expression plasmid and sgRNA to various cell types and gene-editing scenarios. The cell-penetrating α-helical polypeptide enhanced cellular uptake and promoted escape of pCas9 and/or sgRNA from the endosome and transport into the nucleus. The colloidally stable P-HNPs achieved a Cas9 transfection efficiency up to 60% and sgRNA uptake efficiency of 67.4%, representing an improvement over existing polycation-based gene delivery systems. After performing single or multiplex gene editing with an efficiency up to 47.3% in vitro, we demonstrated that P-HNPs delivering Cas9 plasmid/sgRNA targeting the polo-like kinase 1 (Plk1) gene achieved 35% gene deletion in HeLa tumor tissue to reduce the Plk1 protein level by 66.7%, thereby suppressing the tumor growth by >71% and prolonging the animal survival rate to 60% within 60 days. Capable of delivering Cas9 plasmids to various cell types to achieve multiplex gene knock-out, gene knock-in, and gene activation in vitro and in vivo, the P-HNP system offers a versatile gene-editing platform for biological research and therapeutic applications.

scholarly journals The Diversity of Genetic Outcomes from CRISPR/Cas Gene Editing is Regulated by the Length of the Symmetrical Donor DNA Template

Genes ◽  
2020 ◽  
Vol 11 (10) ◽  
pp. 1160
Author(s):  
Amanda M. Hewes ◽  
Brett M. Sansbury ◽  
Eric B. Kmiec
Keyword(s):  
Gene Editing ◽  
Bacterial Cells ◽  
Knock Out ◽  
Viral Genomes ◽  
Homology Directed Repair ◽  
Established Cell ◽  
Dna Template ◽  
Donor Template ◽  
Eukaryotic Genomes ◽  
Cas Gene

Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR)/Cas gene editing systems have enabled molecular geneticists to manipulate prokaryotic and eukaryotic genomes with greater efficiency and precision. CRISPR/Cas provides adaptive immunity in bacterial cells by degrading invading viral genomes. By democratizing this activity into human cells, it is possible to knock out specific genes to disable their function and repair errors. The latter of these activities requires the participation of a single-stranded donor DNA template that provides the genetic information to execute correction in a process referred to as homology directed repair (HDR). Here, we utilized an established cell-free extract system to determine the influence that the donor DNA template length has on the diversity of products from CRISPR-directed gene editing. This model system enables us to view all outcomes of this reaction and reveals that donor template length can influence the efficiency of the reaction and the categories of error-prone products that accompany it. A careful measurement of the products revealed a category of error-prone events that contained the corrected template along with insertions and deletions (indels). Our data provides foundational information for those whose aim is to translate CRISPR/Cas from bench to bedside.

Comparison of gene editing efficiencies of CRISPR/Cas9 and TALEN for generation of MSTN knock-out cashmere goats

2019 ◽  
Vol 132 ◽  
pp. 1-11 ◽  
Author(s):  
Ju Zhang ◽  
Jian Liu ◽  
Wenliang Yang ◽  
MengLan Cui ◽  
Bai Dai ◽  
...  
Keyword(s):  
Gene Editing ◽  
Knock Out ◽  
Cashmere Goats

scholarly journals Inactivation of porcine interleukin-1β results in failure of rapid conceptus elongation

2017 ◽  
Vol 115 (2) ◽  
pp. 307-312 ◽  
Author(s):  
Jeffrey J. Whyte ◽  
Ashley E. Meyer ◽  
Lee D. Spate ◽  
Joshua A. Benne ◽  
Raissa Cecil ◽  
...  
Keyword(s):  
Gene Editing ◽  
Mammalian Species ◽  
Interleukin 1Β ◽  
Corpora Lutea ◽  
Morphological Transition ◽  
Wild Type ◽  
Morphological Transformation ◽  
Proinflammatory Response ◽  
Knock Out ◽  
Estrogen Synthesis

Conceptus expansion throughout the uterus of mammalian species with a noninvasive epitheliochorial type of placentation is critical establishing an adequate uterine surface area for nutrient support during gestation. Pig conceptuses undergo a unique rapid morphological transformation to elongate into filamentous threads within 1 h, which provides the uterine surface to support development and maintain functional corpora lutea through the production of estrogen. Conceptus production of a unique interleukin 1β, IL1B2, temporally increases during the period of trophoblast remodeling during elongation. CRISPR/Cas9 gene editing was used to knock out pig conceptus IL1B2 expression and the secretion of IL1B2 during the time of conceptus elongation. Trophoblast elongation occurred on day 14 in wild-type (IL1B2+/+) conceptuses but did not occur in ILB2-null (IL1B2−/−) conceptuses. Although the morphological transition of IL1B2−/− conceptuses was inhibited, expression of a number of conceptus developmental genes was not altered. However, conceptus aromatase expression and estrogen secretion were decreased, indicating that IL1B2 may be involved in the spatiotemporal increase in conceptus estrogen synthesis needed for the establishment of pregnancy in the pig and may serve to regulate the proinflammatory response of endometrium to IL1B2 during conceptus elongation and attachment to the uterine surface.

scholarly journals Genetic characterization of a mouse line with primary aldosteronism

2017 ◽  
Vol 58 (2) ◽  
pp. 67-78 ◽  
Author(s):  
L G Perez-Rivas ◽  
Y Rhayem ◽  
S Sabrautzki ◽  
C Hantel ◽  
B Rathkolb ◽  
...  
Keyword(s):  
Candidate Genes ◽  
Primary Aldosteronism ◽  
Point Mutations ◽  
Mouse Line ◽  
Enzyme Expression ◽  
Steroidogenic Enzyme ◽  
Knock Out ◽  
Expression Levels ◽  
To Come ◽  
Aldosterone To Renin Ratio

In an attempt to define novel genetic loci involved in the pathophysiology of primary aldosteronism, a mutagenesis screen after treatment with the alkylating agent N-ethyl-N-nitrosourea was established for the parameter aldosterone. One of the generated mouse lines with hyperaldosteronism was phenotypically and genetically characterized. This mouse line had high aldosterone levels but normal creatinine and urea values. The steroidogenic enzyme expression levels in the adrenal gland did not differ significantly among phenotypically affected and unaffected mice. Upon exome sequencing, point mutations were identified in seven candidate genes (Sspo, Dguok, Hoxaas2, Clstn3, Atm, Tipin and Mapk6). Subsequently, animals were stratified into wild-type and mutated groups according to their genotype for each of these candidate genes. A correlation of their genotypes with the respective aldosterone, aldosterone-to-renin ratio (ARR), urea and creatinine values as well as steroidogenic enzyme expression levels was performed. Aldosterone values were significantly higher in animals carrying mutations in four different genes (Sspo, Dguok, Hoxaas2 and Clstn3) and associated statistically significant adrenal Cyp11b2 overexpression as well as increased ARR was present only in mice with Sspo mutation. In contrast, mutations of the remaining candidate genes (Atm, Tipin and Mapk6) were associated with lower aldosterone values and lower Hsd3b6 expression levels. In summary, these data demonstrate association between the genes Sspo, Dguok, Hoxaas2 and Clstn3 and hyperaldosteronism. Final proofs for the causative nature of the mutations have to come from knock-out and knock-in experiments.

Privacy: Potential Violations of Human Dignity

2019 ◽  
Vol 32 (2) ◽  
pp. 106-107
Author(s):  
Constance L. Milton
Keyword(s):  
Human Dignity ◽  
Gene Editing ◽  
Personal Information ◽  
Genetic Material ◽  
Privacy Concerns ◽  
The Right ◽  
Genetic Structures

Privacy has been understood as a bioethical concept whose focus is on personal choosing or the right to control access to self. In nursing, privacy concerns abound where there is potential for the violation of human dignity as scientific advancements in genetic biotechnology potentially disclose personal information and genetic structures are made known to others without the consent of persons whose genetic material is being utilized for biological experimentation. In this article, the author offers new insights into the concept of privacy and human dignity as gene editing and its possible consequences unfurl within the scientific and healthcare arenas. A humanbecoming ethos perspective for nursing is illuminated.

Sign in / Sign up

Export Citation Format

Share Document