scholarly journals Base pair editing of goat embryos: nonsense codon introgression into FGF5 to improve cashmere yield

2018 ◽  
Author(s):  
Guanwei Li ◽  
Shiwei Zhou ◽  
Chao Li ◽  
Bei Cai ◽  
Honghao Yu ◽  
...  
Keyword(s):  
Tissue Type ◽  
Large Animal ◽  
Production Traits ◽  
Dna Double Strand Breaks ◽  
Single Base ◽  
Base Editing ◽  
Large Animal Models ◽  
A Genome ◽  
Target Sites ◽  
Nonsense Codons

AbstractThe ability to alter single bases without DNA double strand breaks provides a potential solution for multiplex editing of livestock genomes for quantitative traits. Here, we report using a single base editing system, Base Editor 3 (BE3), to induce nonsense codons (C-to-T transitions) at four target sites in caprine FGF5. All five progenies produced from microinjected single-cell embryos had alleles with a targeted nonsense mutation and yielded expected phenotypes. The effectiveness of BE3 to make single base changes varied considerably based on sgRNA design. Also, the rate of mosaicism differed between animals, target sites, and tissue type. PCR amplicon and whole genome resequencing analyses for off-target changes caused by BE3 were low at a genome-wide scale. This study provides first evidence of base editing in livestock, thus presenting a potentially better method to introgress complex human disease alleles into large animal models and provide genetic improvement of complex health and production traits in a single generation.

scholarly journals Application of the Modified Cytosine Base-Editing in the Cultured Cells of Bama Minipig

2021 ◽  
Author(s):  
Jia-sheng Pan ◽  
Zi-sheng Lin ◽  
Jian-cong Wen ◽  
Jian-feng Guo ◽  
Xia-hui Wu ◽  
...  
Keyword(s):  
Genome Editing ◽  
Base Pair ◽  
Double Strand Breaks ◽  
Fibroblast Cells ◽  
Dna Double Strand Breaks ◽  
Strand Breaks ◽  
Single Base ◽  
Lean Meat ◽  
Base Editing ◽  
Target Effects

Abstract Bama minipig is a unique miniature swine bred from China. Their favorable characteristics include delicious meat, strong adaptability, tolerance to rough feed, and high levels of stress tolerance. Unfavorable characteristics are their low lean meat percentage, high fat content, slow growth rate, and low feed conversion ratio. Genome-editing technology using CRISPR/Cas9 efficiently knocked out the myostatin gene (MSTN) that has a negative regulatory effect on muscle production, effectively promoting pig muscle growth and increasing lean meat percentage of the pigs. However, CRISPR/Cas9 genome editing technology is based on random mutations implemented by DNA double-strand breaks, which may trigger genomic off-target effects and chromosomal rearrangements. The application of CRISPR/Cas9 to improve economic traits in pigs has raised biosafety concerns. Base editor (BE) developed based on CRISPR/Cas9 such as cytosine base editor (CBE) effectively achieve targeted modification of a single base without relying on DNA double-strand breaks. Hence, the method has greater safety in the genetic improvement of pigs. The aim of the present study is to utilize a modified CBE to generate MSTN-knockout cells of Bama minipigs. Our results showed that the constructed “all-in-one”-modified CBE plasmid achieved directional conversion of a single C·G base pair to a T·A base pair of the MSTN target in Bama miniature pig fibroblast cells. We successfully constructed multiple single-cell colonies of Bama minipigs fibroblast cells carrying the MSTN premature termination and verified that there were no genomic off-target effects detected. This study provides a foundation for further application of somatic cell cloning to construct MSTN-edited Bama minipigs that carry only a single-base mutation and avoids biosafety risks to a large extent, thereby providing experience and a reference for the base editing of other genetic loci in Bama minipigs.

scholarly journals BEAR reveals that increased fidelity variants can successfully reduce the mismatch-tolerance of adenine but not cytosine base editors

2020 ◽  
Author(s):  
András Tálas ◽  
Dorottya Simon ◽  
Péter Kulcsár ◽  
Éva Varga ◽  
Ervin Welker
Keyword(s):  
High Throughput ◽  
Double Strand Breaks ◽  
Dna Double Strand Breaks ◽  
Strand Breaks ◽  
Single Base ◽  
Base Editing ◽  
Target Effects

Abstract Adenine and cytosine base editors (ABE, CBE) are designed to generate single base mutations in genes without necessarily generating DNA double-strand breaks and undesired indel mutations. However, the activity of base editors employing an inactive (dead) SpCas9 is generally low, which may be increased only at the expense of generating undesired indels by using a nickase SpCas9. We have increased the efficiency of dead base editors to a level comparable to that of nickase base editors by enriching cells labelled for efficient base editing using Base Editor Activity Reporter (BEAR), a plasmid-based, fluorescent tool. Furthermore, by exploiting the semi-high-throughput potential of BEAR, we have examined the applicability of increased fidelity variants to decrease Cas9-dependent off-target effects that revealed that CBE remains active on off-targets where increased fidelity mutations and/or mismatches decrease the activity of ABE, making the strategy of applying increased fidelity variants more beneficial for ABE than for CBE.

scholarly journals Genome-wide interrogation of gene functions through base editor screens empowered by barcoded sgRNAs

2020 ◽  
Author(s):  
Ping Xu ◽  
Zhiheng Liu ◽  
Ying Liu ◽  
Huazheng Ma ◽  
Yiyuan Xu ◽  
...  
Keyword(s):  
Dna Cleavage ◽  
Gene Knockout ◽  
Screening Strategy ◽  
Dna Double Strand Breaks ◽  
Base Editing ◽  
Cell Library ◽  
A Genome ◽  
Lentiviral Infection ◽  
A Cell ◽  
Genome Scale

Abstract Canonical CRISPR screens rely on Cas9-induced DNA double-strand breaks (DSBs) to generate targeted gene knockouts. These DSB-dependent methodologies may yield false-positive results by mistakenly assuming targeted loci as essential for cell viability, especially when high-copy-number sites are targeted. Here, we use CRISPR cytosine base editors for genome-scale knockout screens by perturbing gene start codons or splice sites, or by introducing premature termination codons (PTCs). Combining with iBAR strategy we have previously established, we realized an iBARed cytosine Base Editing-mediated gene KnockOut (BARBEKO) screening strategy at a genome-scale (targeting 17,501 genes) in multiple human cell lines. By constructing such a cell library through lentiviral infection at a high MOI (up to 10), we significantly reduced starting cells while producing screening results with improved efficiency and accuracy. More importantly, in comparison with Cas9-mediated cell fitness screens, BARBEKO screens are no longer affected by DNA-cleavage induced cytotoxicity in HeLa, K562, or DSB-sensitive RPE1 cells. We anticipate that BARBEKO offers a valuable tool to complement the current CRISPR screens in various settings.

scholarly journals Molecular Mechanisms of Fetal Tendon Regeneration Versus Adult Fibrous Repair

2021 ◽  
Vol 22 (11) ◽  
pp. 5619
Author(s):  
Iris Ribitsch ◽  
Andrea Bileck ◽  
Alexander D. Aldoshin ◽  
Maciej M. Kańduła ◽  
Rupert L. Mayer ◽  
...  
Keyword(s):  
Extracellular Matrix ◽  
Molecular Mechanisms ◽  
Unmet Need ◽  
Tendon Healing ◽  
Tendon Injury ◽  
Inflammatory Factors ◽  
Large Animal ◽  
Post Injury ◽  
Tendon Regeneration ◽  
Large Animal Models

Tendinopathies are painful, disabling conditions that afflict 25% of the adult human population. Filling an unmet need for realistic large-animal models, we here present an ovine model of tendon injury for the comparative study of adult scarring repair and fetal regeneration. Complete regeneration of the fetal tendon within 28 days is demonstrated, while adult tendon defects remained macroscopically and histologically evident five months post-injury. In addition to a comprehensive histological assessment, proteome analyses of secretomes were performed. Confirming histological data, a specific and pronounced inflammation accompanied by activation of neutrophils in adult tendon defects was observed, corroborated by the significant up-regulation of pro-inflammatory factors, neutrophil attracting chemokines, the release of potentially tissue-damaging antimicrobial and extracellular matrix-degrading enzymes, and a response to oxidative stress. In contrast, secreted proteins of injured fetal tendons included proteins initiating the resolution of inflammation or promoting functional extracellular matrix production. These results demonstrate the power and relevance of our novel ovine fetal tendon regeneration model, which thus promises to accelerate research in the field. First insights from the model already support our molecular understanding of successful fetal tendon healing processes and may guide improved therapeutic strategies.

scholarly journals Mapping CRISPR-Cas9 public and commercial innovation using The Lens institutional toolkit

2021 ◽  
Author(s):  
Osmat Azzam Jefferson ◽  
Simon Lang ◽  
Kenny Williams ◽  
Deniz Koellhofer ◽  
Aaron Ballagh ◽  
...  
Keyword(s):  
Public Investment ◽  
Open Data ◽  
Regulatory Elements ◽  
Policy Makers ◽  
Base Editing ◽  
The Public ◽  
Homology Directed Repair ◽  
A Genome ◽  
Institutional Capability ◽  
Cellular Dna

AbstractCRISPR-Cas9 is a revolutionary technology because it is precise, fast and easy to implement, cheap and components are readily accessible. This versatility means that the technology can deliver a timely end product and can be used by many stakeholders. In plant cells, the technology can be applied to knockout genes by using CRISPR–Cas nucleases that can alter coding gene regions or regulatory elements, alter precisely a genome by base editing to delete or regulate gene expression, edit precisely a genome by homology-directed repair mechanism (cellular DNA), or regulate transcriptional machinery by using dead Cas proteins to recruit regulators to the promoter region of a gene. All these applications can be for: 1) Research use (Non commercial), 2) Uses related product components for the technology itself (reagents, equipment, toolkits, vectors etc), and 3) Uses related to the development and sale of derived end products based on this technology. In this contribution, we present a prototype report that can engage the community in open, inclusive and collaborative innovation mapping. Using the open data at the Lens.org platform and other relevant sources, we tracked, analyzed, organized, and assembled contextual and bridged patent and scholarly knowledge about CRISPR-Cas9 and with the assistance of a new Lens institutional capability, The Lens Report Builder, currently in beta release, mapped the public and commercial innovation pathways of the technology. When scaled, this capability will also enable coordinated editing and curation by credentialed experts to inform policy makers, businesses and private or public investment.

scholarly journals Hyperinsulinaemic hypoglycaemia in non-anaesthetized Göttingen minipigs induces a counter-regulatory endocrine response and electrocardiographic changes

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Mille K. Lyhne ◽  
Andreas Vegge ◽  
Gro Klitgaard Povlsen ◽  
Rita Slaaby ◽  
Jonas Kildegaard ◽  
...  
Keyword(s):  
Plasma Glucose ◽  
Fold Increase ◽  
Diabetic Group ◽  
Large Animal ◽  
Qtc Interval ◽  
Interval Prolongation ◽  
Hyperinsulinaemic Hypoglycaemia ◽  
Large Animal Models ◽  
Qtc Interval Prolongation ◽  
Electrocardiographic Recordings

AbstractThe potentially fatal cardiovascular effects of hypoglycaemia are not well understood and large animal models of the counter-regulatory responses and cardiovascular consequences of insulin-induced hypoglycaemia are needed to understand the mechanisms in humans. The aim of this study was to develop a human-like minipig model of hypoglycaemia including healthy and diabetic pigs to investigate endocrine, electrocardiographic and platelet effects. Hypoglycaemia was induced using a hyperinsulinaemic, hypoglycaemic clamp and an insulin bolus protocol. Plasma glucose, glucagon, C-peptide, insulin, epinephrine and platelet aggregation responses were measured before, during and after hypoglycaemia. Continuous electrocardiographic recordings were obtained. Hypoglycaemia at a plasma glucose concentration of 0.8–1.0 mM in the clamp induced 25-fold increase in epinephrine and sixfold and threefold increase in glucagon for healthy and diabetic pigs, respectively. The hypoglycaemic clamp induced QTc-interval prolongation and increase in cardiac arrhythmias. In the bolus approach, the non-diabetic group reached plasma glucose target of 1.5 mM and QTc-interval was prolonged after insulin injection, but before glucose nadir. The diabetic group did not reach hypoglycaemic target, but still demonstrated QTc-interval prolongation. These results demonstrate effects of hyperinsulinaemic hypoglycaemia closely resembling human physiology, indicating the minipig as a translational animal model of counter-regulatory endocrine and myocardial effects of hypoglycaemia.

scholarly journals Large Animal Models for Investigating Cell Therapies of Stress Urinary Incontinence

2021 ◽  
Vol 22 (11) ◽  
pp. 6092
Author(s):  
Bastian Amend ◽  
Niklas Harland ◽  
Jasmin Knoll ◽  
Arnulf Stenzl ◽  
Wilhelm K. Aicher
Keyword(s):  
Urinary Incontinence ◽  
Stress Urinary Incontinence ◽  
Animal Models ◽  
Clinical Situation ◽  
Surgical Instruments ◽  
Health Concern ◽  
Large Animal ◽  
Knock Out ◽  
Cell Therapies ◽  
Large Animal Models

Stress urinary incontinence (SUI) is a significant health concern for patients affected, impacting their quality of life severely. To investigate mechanisms contributing to SUI different animal models were developed. Incontinence was induced under defined conditions to explore the pathomechanisms involved, spontaneous recovery, or efficacy of therapies over time. The animal models were coined to mimic known SUI risk factors such as childbirth or surgical injury. However, animal models neither reflect the human situation completely nor the multiple mechanisms that ultimately contribute to the pathogenesis of SUI. In the past, most SUI animal studies took advantage of rodents or rabbits. Recent models present for instance transgenic rats developing severe obesity, to investigate metabolic interrelations between the disorder and incontinence. Using recombinant gene technologies, such as transgenic, gene knock-out or CRISPR-Cas animals may narrow the gap between the model and the clinical situation of patients. However, to investigate surgical regimens or cell therapies to improve or even cure SUI, large animal models such as pig, goat, dog and others provide several advantages. Among them, standard surgical instruments can be employed for minimally invasive transurethral diagnoses and therapies. We, therefore, focus in this review on large animal models of SUI.

scholarly journals A Nonsense Variant in Hephaestin Like 1 (HEPHL1) Is Responsible for Congenital Hypotrichosis in Belted Galloway Cattle

Genes ◽  
2021 ◽  
Vol 12 (5) ◽  
pp. 643
Author(s):  
Thibaud Kuca ◽  
Brandy M. Marron ◽  
Joana G. P. Jacinto ◽  
Julia M. Paris ◽  
Christian Gerspach ◽  
...  
Keyword(s):  
Genome Wide Association Study ◽  
Homozygosity Mapping ◽  
Mendelian Inheritance ◽  
Large Animal Model ◽  
Large Animal ◽  
Loss Of Function ◽  
Protein Coding ◽  
Positional Candidate ◽  
Genome Wide ◽  
A Genome

Genodermatosis such as hair disorders mostly follow a monogenic mode of inheritance. Congenital hypotrichosis (HY) belong to this group of disorders and is characterized by abnormally reduced hair since birth. The purpose of this study was to characterize the clinical phenotype of a breed-specific non-syndromic form of HY in Belted Galloway cattle and to identify the causative genetic variant for this recessive disorder. An affected calf born in Switzerland presented with multiple small to large areas of alopecia on the limbs and on the dorsal part of the head, neck, and back. A genome-wide association study using Swiss and US Belted Galloway cattle encompassing 12 cases and 61 controls revealed an association signal on chromosome 29. Homozygosity mapping in a subset of cases refined the HY locus to a 1.5 Mb critical interval and subsequent Sanger sequencing of protein-coding exons of positional candidate genes revealed a stop gain variant in the HEPHL1 gene that encodes a multi-copper ferroxidase protein so-called hephaestin like 1 (c.1684A>T; p.Lys562*). A perfect concordance between the homozygous presence of this most likely pathogenic loss-of-function variant and the HY phenotype was found. Genotyping of more than 700 purebred Swiss and US Belted Galloway cattle showed the global spread of the mutation. This study provides a molecular test that will permit the avoidance of risk matings by systematic genotyping of relevant breeding animals. This rare recessive HEPHL1-related form of hypotrichosis provides a novel large animal model for similar human conditions. The results have been incorporated in the Online Mendelian Inheritance in Animals (OMIA) database (OMIA 002230-9913).

Sign in / Sign up

Export Citation Format

Share Document