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Dorner L, Stratmann B, Bader L, Podobnik M, Irion U. Efficient genome editing using modified Cas9 proteins in zebrafish. Biol Open 2024; 13:bio060401. [PMID: 38545958 PMCID: PMC10997048 DOI: 10.1242/bio.060401] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2024] [Accepted: 03/12/2024] [Indexed: 04/07/2024] Open
Abstract
The zebrafish (Danio rerio) is an important model organism for basic as well as applied bio-medical research. One main advantage is its genetic tractability, which was greatly enhanced by the introduction of the CRISPR/Cas method a decade ago. The generation of loss-of-function alleles via the production of small insertions or deletions in the coding sequences of genes with CRISPR/Cas systems is now routinely achieved with high efficiency. The method is based on the error prone repair of precisely targeted DNA double strand breaks by non-homologous end joining (NHEJ) in the cell nucleus. However, editing the genome with base pair precision, by homology-directed repair (HDR), is by far less efficient and therefore often requires large-scale screening of potential carriers by labour intensive genotyping. Here we confirm that the Cas9 protein variant SpRY, with relaxed PAM requirement, can be used to target some sites in the zebrafish genome. In addition, we demonstrate that the incorporation of an artificial nuclear localisation signal (aNLS) into the Cas9 protein variants not only enhances the efficiency of gene knockout but also the frequency of HDR, thereby facilitating the efficient modification of single base pairs in the genome. Our protocols provide a guide for a cost-effective generation of versatile and potent Cas9 protein variants and efficient gene editing in zebrafish.
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Affiliation(s)
- Laura Dorner
- Max Planck Institute for Biology, RG Colour Pattern Evolution, Tuebingen, Max-Planck-Ring 5, 72076 Tuebingen, Germany
| | - Benedikt Stratmann
- Max Planck Institute for Biology, RG Colour Pattern Evolution, Tuebingen, Max-Planck-Ring 5, 72076 Tuebingen, Germany
| | - Laura Bader
- Max Planck Institute for Biology, RG Colour Pattern Evolution, Tuebingen, Max-Planck-Ring 5, 72076 Tuebingen, Germany
| | - Marco Podobnik
- Max Planck Institute for Biology, RG Colour Pattern Evolution, Tuebingen, Max-Planck-Ring 5, 72076 Tuebingen, Germany
| | - Uwe Irion
- Max Planck Institute for Biology, RG Colour Pattern Evolution, Tuebingen, Max-Planck-Ring 5, 72076 Tuebingen, Germany
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Szelenyi ER, Navarrete JS, Murry AD, Zhang Y, Girven KS, Kuo L, Cline MM, Bernstein MX, Burdyniuk M, Bowler B, Goodwin NL, Juarez B, Zweifel LS, Golden SA. An arginine-rich nuclear localization signal (ArgiNLS) strategy for streamlined image segmentation of single-cells. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.11.22.568319. [PMID: 38045271 PMCID: PMC10690249 DOI: 10.1101/2023.11.22.568319] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/05/2023]
Abstract
High-throughput volumetric fluorescent microscopy pipelines can spatially integrate whole-brain structure and function at the foundational level of single-cells. However, conventional fluorescent protein (FP) modifications used to discriminate single-cells possess limited efficacy or are detrimental to cellular health. Here, we introduce a synthetic and non-deleterious nuclear localization signal (NLS) tag strategy, called 'Arginine-rich NLS' (ArgiNLS), that optimizes genetic labeling and downstream image segmentation of single-cells by restricting FP localization near-exclusively in the nucleus through a poly-arginine mechanism. A single N-terminal ArgiNLS tag provides modular nuclear restriction consistently across spectrally separate FP variants. ArgiNLS performance in vivo displays functional conservation across major cortical cell classes, and in response to both local and systemic brain wide AAV administration. Crucially, the high signal-to-noise ratio afforded by ArgiNLS enhances ML-automated segmentation of single-cells due to rapid classifier training and enrichment of labeled cell detection within 2D brain sections or 3D volumetric whole-brain image datasets, derived from both staining-amplified and native signal. This genetic strategy provides a simple and flexible basis for precise image segmentation of genetically labeled single-cells at scale and paired with behavioral procedures.
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Affiliation(s)
- Eric R. Szelenyi
- University of Washington Center of Excellence in Neurobiology of Addiction, Pain, and Emotion (NAPE), Seattle, WA, USA
- University of Washington, Department of Biological Structure, Seattle, WA, USA
| | - Jovana S. Navarrete
- University of Washington Center of Excellence in Neurobiology of Addiction, Pain, and Emotion (NAPE), Seattle, WA, USA
- University of Washington, Department of Biological Structure, Seattle, WA, USA
- University of Washington, Graduate Program in Neuroscience, Seattle, WA, USA
| | - Alexandria D. Murry
- University of Washington Center of Excellence in Neurobiology of Addiction, Pain, and Emotion (NAPE), Seattle, WA, USA
- University of Washington, Department of Biological Structure, Seattle, WA, USA
| | - Yizhe Zhang
- University of Washington Center of Excellence in Neurobiology of Addiction, Pain, and Emotion (NAPE), Seattle, WA, USA
- University of Washington, Department of Biological Structure, Seattle, WA, USA
| | - Kasey S. Girven
- University of Washington, Department of Anesthesiology and Pain Medicine
| | - Lauren Kuo
- University of Washington Center of Excellence in Neurobiology of Addiction, Pain, and Emotion (NAPE), Seattle, WA, USA
- University of Washington Undergraduate Program in Biochemistry
- Allen Institute for Cell Science, Seattle, WA, USA
| | - Marcella M. Cline
- University of Washington Center of Excellence in Neurobiology of Addiction, Pain, and Emotion (NAPE), Seattle, WA, USA
- University of Washington, Department of Pharmacology, Seattle, WA, USA
- Cajal Neuroscience, Seattle, WA, USA
| | - Mollie X. Bernstein
- University of Washington Center of Excellence in Neurobiology of Addiction, Pain, and Emotion (NAPE), Seattle, WA, USA
- University of Washington, Department of Pharmacology, Seattle, WA, USA
| | | | - Bryce Bowler
- University of Washington, Department of Biological Structure, Seattle, WA, USA
| | - Nastacia L. Goodwin
- University of Washington Center of Excellence in Neurobiology of Addiction, Pain, and Emotion (NAPE), Seattle, WA, USA
- University of Washington, Department of Biological Structure, Seattle, WA, USA
- University of Washington, Graduate Program in Neuroscience, Seattle, WA, USA
| | - Barbara Juarez
- University of Washington Center of Excellence in Neurobiology of Addiction, Pain, and Emotion (NAPE), Seattle, WA, USA
- University of Washington, Department of Psychiatry and Behavioral Sciences, Seattle, WA, USA
- University of Washington, Department of Pharmacology, Seattle, WA, USA
- University of Maryland School of Medicine, Department of Neurobiology, Baltimore, MD, USA
| | - Larry S. Zweifel
- University of Washington Center of Excellence in Neurobiology of Addiction, Pain, and Emotion (NAPE), Seattle, WA, USA
- University of Washington, Department of Psychiatry and Behavioral Sciences, Seattle, WA, USA
- University of Washington, Department of Pharmacology, Seattle, WA, USA
| | - Sam A. Golden
- University of Washington Center of Excellence in Neurobiology of Addiction, Pain, and Emotion (NAPE), Seattle, WA, USA
- University of Washington, Department of Biological Structure, Seattle, WA, USA
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Doering L, Cornean A, Thumberger T, Benjaminsen J, Wittbrodt B, Kellner T, Hammouda OT, Gorenflo M, Wittbrodt J, Gierten J. CRISPR-based knockout and base editing confirm the role of MYRF in heart development and congenital heart disease. Dis Model Mech 2023; 16:dmm049811. [PMID: 37584388 PMCID: PMC10445736 DOI: 10.1242/dmm.049811] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2022] [Accepted: 07/21/2023] [Indexed: 08/17/2023] Open
Abstract
High-throughput DNA sequencing studies increasingly associate DNA variants with congenital heart disease (CHD). However, functional modeling is a crucial prerequisite for translating genomic data into clinical care. We used CRISPR-Cas9-mediated targeting of 12 candidate genes in the vertebrate model medaka (Oryzias latipes), five of which displayed a novel cardiovascular phenotype spectrum in F0 (crispants): mapre2, smg7, cdc42bpab, ankrd11 and myrf, encoding a transcription factor recently linked to cardiac-urogenital syndrome. Our myrf mutant line showed particularly prominent embryonic cardiac defects recapitulating phenotypes of pediatric patients, including hypoplastic ventricle. Mimicking human mutations, we edited three sites to generate specific myrf single-nucleotide variants via cytosine and adenine base editors. The Glu749Lys missense mutation in the conserved intramolecular chaperon autocleavage domain fully recapitulated the characteristic myrf mutant phenotype with high penetrance, underlining the crucial function of this protein domain. The efficiency and scalability of base editing to model specific point mutations accelerate gene validation studies and the generation of human-relevant disease models.
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Affiliation(s)
- Lino Doering
- Centre for Organismal Studies, Heidelberg University, 69120 Heidelberg, Germany
- Department of Pediatric Cardiology, University Hospital Heidelberg, 69120 Heidelberg, Germany
| | - Alex Cornean
- Centre for Organismal Studies, Heidelberg University, 69120 Heidelberg, Germany
- Heidelberg Biosciences International Graduate School, Heidelberg University, 69120 Heidelberg, Germany
| | - Thomas Thumberger
- Centre for Organismal Studies, Heidelberg University, 69120 Heidelberg, Germany
| | - Joergen Benjaminsen
- Centre for Organismal Studies, Heidelberg University, 69120 Heidelberg, Germany
| | - Beate Wittbrodt
- Centre for Organismal Studies, Heidelberg University, 69120 Heidelberg, Germany
| | - Tanja Kellner
- Centre for Organismal Studies, Heidelberg University, 69120 Heidelberg, Germany
| | - Omar T. Hammouda
- Centre for Organismal Studies, Heidelberg University, 69120 Heidelberg, Germany
| | - Matthias Gorenflo
- Department of Pediatric Cardiology, University Hospital Heidelberg, 69120 Heidelberg, Germany
- DZHK (German Centre for Cardiovascular Research), partner site Heidelberg/Mannheim, 69120 Heidelberg, Germany
| | - Joachim Wittbrodt
- Centre for Organismal Studies, Heidelberg University, 69120 Heidelberg, Germany
- DZHK (German Centre for Cardiovascular Research), partner site Heidelberg/Mannheim, 69120 Heidelberg, Germany
| | - Jakob Gierten
- Centre for Organismal Studies, Heidelberg University, 69120 Heidelberg, Germany
- Department of Pediatric Cardiology, University Hospital Heidelberg, 69120 Heidelberg, Germany
- DZHK (German Centre for Cardiovascular Research), partner site Heidelberg/Mannheim, 69120 Heidelberg, Germany
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Medert R, Thumberger T, Tavhelidse-Suck T, Hub T, Kellner T, Oguchi Y, Dlugosz S, Zimmermann F, Wittbrodt J, Freichel M. Efficient single copy integration via homology-directed repair (scHDR) by 5'modification of large DNA donor fragments in mice. Nucleic Acids Res 2023; 51:e14. [PMID: 36533445 PMCID: PMC10021492 DOI: 10.1093/nar/gkac1150] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2021] [Revised: 09/22/2022] [Accepted: 12/12/2022] [Indexed: 12/23/2022] Open
Abstract
CRISPR/Cas-based approaches have largely replaced conventional gene targeting strategies. However, homology-directed repair (HDR) in the mouse genome is not very efficient, and precisely inserting longer sequences using HDR remains challenging given that donor constructs preferentially integrate as concatemers. Here, we showed that injecting 5' biotinylated donor DNA into mouse embryos at the two-cell stage led to efficient single-copy HDR (scHDR) allele generation. Our dedicated genotyping strategy showed that these alleles occurred with frequencies of 19%, 20%, and 26% at three independent gene loci, indicating that scHDR was dramatically increased by 5' biotinylation. Thus, we suggest that the combination of a 5' biotinylated donor and diligent analysis of concatemer integration are prerequisites for efficiently and reliably generating conditional alleles or other large fragment knock-ins in the mouse genome.
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Affiliation(s)
- Rebekka Medert
- Institute of Pharmacology, Heidelberg University, Heidelberg, Germany.,DZHK (German Centre for Cardiovascular Research), partner site Heidelberg/Mannheim, Heidelberg, Germany
| | - Thomas Thumberger
- Centre for Organismal Studies, Heidelberg University, Heidelberg, Germany
| | | | - Tobias Hub
- Institute of Pharmacology, Heidelberg University, Heidelberg, Germany
| | - Tanja Kellner
- Centre for Organismal Studies, Heidelberg University, Heidelberg, Germany
| | - Yoko Oguchi
- Institute of Pharmacology, Heidelberg University, Heidelberg, Germany
| | - Sascha Dlugosz
- Interfacultary Biomedical Faculty (IBF), Heidelberg University, Heidelberg, Germany
| | - Frank Zimmermann
- Interfacultary Biomedical Faculty (IBF), Heidelberg University, Heidelberg, Germany
| | - Joachim Wittbrodt
- Centre for Organismal Studies, Heidelberg University, Heidelberg, Germany
| | - Marc Freichel
- Institute of Pharmacology, Heidelberg University, Heidelberg, Germany.,DZHK (German Centre for Cardiovascular Research), partner site Heidelberg/Mannheim, Heidelberg, Germany
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Pakari K, Wittbrodt J, Thumberger T. De novo PAM generation to reach initially inaccessible target sites for base editing. Development 2023; 150:286701. [PMID: 36683434 PMCID: PMC10110497 DOI: 10.1242/dev.201115] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2022] [Accepted: 12/16/2022] [Indexed: 01/24/2023]
Abstract
Base editing by CRISPR crucially depends on the presence of a protospacer adjacent motif (PAM) at the correct distance from the editing site. Here, we present and validate an efficient one-shot approach termed 'inception' that expands the editing range. This is achieved by sequential, combinatorial base editing: de novo generated synonymous, non-synonymous or intronic PAM sites facilitate subsequent base editing at nucleotide positions that were initially inaccessible, further opening the targeting range of highly precise editing approaches. We demonstrate the applicability of the inception concept in medaka (Oryzias latipes) in three settings: loss of function, by introducing a pre-termination STOP codon in the open reading frame of oca2; locally confined multi-codon changes to generate allelic variants with different phenotypic severity in kcnh6a; and the removal of a splice acceptor site by targeting intronic sequences of rx3. Using sequentially acting base editors in the described combinatorial approach expands the number of accessible target sites by 65% on average. This allows the use of well-established tools with NGG PAM recognition for the establishment of thus far unreachable disease models, for hypomorphic allele studies and for efficient targeted mechanistic investigations in a precise and predictable manner.
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Affiliation(s)
- Kaisa Pakari
- Centre for Organismal Studies Heidelberg (COS), Heidelberg University, Im Neuenheimer Feld 230, 69120 Heidelberg, Germany.,Heidelberg Biosciences International Graduate School (HBIGS), Heidelberg University, Im Neuenheimer Feld 501, 69120 Heidelberg, Germany
| | - Joachim Wittbrodt
- Centre for Organismal Studies Heidelberg (COS), Heidelberg University, Im Neuenheimer Feld 230, 69120 Heidelberg, Germany
| | - Thomas Thumberger
- Centre for Organismal Studies Heidelberg (COS), Heidelberg University, Im Neuenheimer Feld 230, 69120 Heidelberg, Germany
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Aquatic Freshwater Vertebrate Models of Epilepsy Pathology: Past Discoveries and Future Directions for Therapeutic Discovery. Int J Mol Sci 2022; 23:ijms23158608. [PMID: 35955745 PMCID: PMC9368815 DOI: 10.3390/ijms23158608] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2022] [Revised: 07/29/2022] [Accepted: 07/30/2022] [Indexed: 12/04/2022] Open
Abstract
Epilepsy is an international public health concern that greatly affects patients’ health and lifestyle. About 30% of patients do not respond to available therapies, making new research models important for further drug discovery. Aquatic vertebrates present a promising avenue for improved seizure drug screening and discovery. Zebrafish (Danio rerio) and African clawed frogs (Xenopus laevis and tropicalis) are increasing in popularity for seizure research due to their cost-effective housing and rearing, similar genome to humans, ease of genetic manipulation, and simplicity of drug dosing. These organisms have demonstrated utility in a variety of seizure-induction models including chemical and genetic methods. Past studies with these methods have produced promising data and generated questions for further applications of these models to promote discovery of drug-resistant seizure pathology and lead to effective treatments for these patients.
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Cornean A, Gierten J, Welz B, Mateo JL, Thumberger T, Wittbrodt J. Precise in vivo functional analysis of DNA variants with base editing using ACEofBASEs target prediction. eLife 2022; 11:72124. [PMID: 35373735 PMCID: PMC9033269 DOI: 10.7554/elife.72124] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2021] [Accepted: 03/21/2022] [Indexed: 11/18/2022] Open
Abstract
Single nucleotide variants (SNVs) are prevalent genetic factors shaping individual trait profiles and disease susceptibility. The recent development and optimizations of base editors, rubber and pencil genome editing tools now promise to enable direct functional assessment of SNVs in model organisms. However, the lack of bioinformatic tools aiding target prediction limits the application of base editing in vivo. Here, we provide a framework for adenine and cytosine base editing in medaka (Oryzias latipes) and zebrafish (Danio rerio), ideal for scalable validation studies. We developed an online base editing tool ACEofBASEs (a careful evaluation of base-edits), to facilitate decision-making by streamlining sgRNA design and performing off-target evaluation. We used state-of-the-art adenine (ABE) and cytosine base editors (CBE) in medaka and zebrafish to edit eye pigmentation genes and transgenic GFP function with high efficiencies. Base editing in the genes encoding troponin T and the potassium channel ERG faithfully recreated known cardiac phenotypes. Deep-sequencing of alleles revealed the abundance of intended edits in comparison to low levels of insertion or deletion (indel) events for ABE8e and evoBE4max. We finally validated missense mutations in novel candidate genes of congenital heart disease (CHD) dapk3, ube2b, usp44, and ptpn11 in F0 and F1 for a subset of these target genes with genotype-phenotype correlation. This base editing framework applies to a wide range of SNV-susceptible traits accessible in fish, facilitating straight-forward candidate validation and prioritization for detailed mechanistic downstream studies. DNA contains sequences of four different molecules known as bases that represent our genetic code. In a mutation called a single nucleotide variant (or SNV for short), a single base in the sequence is swapped for another base. This can lead the individual carrying this SNV to produce a slightly different version of a protein to that found in other people. This slightly different protein may not work properly, or may perform a different task. In recent years, researchers have identified thousands of SNVs in humans linked with congenital heart diseases, but the roles of many of these SNVs remain unclear. Tools known as base editors allow researchers to efficiently modify single bases in DNA. Base editors use molecules known as short guide RNAs (or sgRNAs for short) to direct enzymes to specific positions in the DNA to swap, delete or insert a base. The sgRNAs need to be carefully designed to target the correct bases, however, which is a time consuming process. Furthermore, base editors were developed in cells grown in laboratories and so far only a few studies have demonstrated how they could be used in living animals. To overcome these limitations, Cornean, Gierten, Welz et al. developed a framework for base editing in two species of fish that are often used as models in research, namely medaka and zebrafish. The framework uses existing base editors that swap individual target bases and a new online tool – referred to as ACEofBASEs – to help design the required sgRNAs. The team were able to use the framework to characterize the medaka equivalents of four SNVs that have been previously associated with congenital heart disease in humans. The new framework developed here will help researchers to investigate the roles of SNVs in fish and other animals and validate human disease candidates. This approach could also be used to study the various ways that cells modify proteins by changing the specific bases involved in such modifications.
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Affiliation(s)
- Alex Cornean
- Centre for Organismal Studies, Heidelberg University, Heidelberg, Germany
| | - Jakob Gierten
- Centre for Organismal Studies, Heidelberg University, Heidelberg, Germany
| | - Bettina Welz
- Centre for Organismal Studies, Heidelberg University, Heidelberg, Germany
| | - Juan Luis Mateo
- Deparment of Computer Science, University of Oviedo, Oviedo, Spain
| | - Thomas Thumberger
- Centre for Organismal Studies, Heidelberg University, Heidelberg, Germany
| | - Joachim Wittbrodt
- Centre for Organismal Studies, Heidelberg University, Heidelberg, Germany
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