Background: Medaka () is a popular animal model used in vertebrate genetic analysis. Recently, an efficient (~ 30%) knock-in system via non-homologous end joining (NHEJ) was established in zebrafish using the CRISPR/Cas9 system. If the same technique were applicable in medaka, it would greatly expand the usefulness of this model organism. The question of the applicability of CRISPR/Cas9 in medaka, however, has yet to be addressed.
Results: We report the highly efficient generation of knock-in transgenic medaka via non-homologous end joining (NHEJ). Donor plasmid containing a heat-shock promoter and a reporter gene was co-injected with a short guide RNA (sgRNA) targeted for genome digestion, an sgRNA targeted for donor plasmid digestion, and Cas9 mRNA. Broad transgene expression in the expression domain of a target gene was observed in approximately 25% of injected embryos. By raising these animals, we established stable knock-in transgenic fish with several different constructs for five genetic loci, obtaining transgenic founders at efficiencies of > 50% for all five loci. Further, we show that the method is useful for obtaining mutant alleles. In the experiments where transgene integrations were targeted between the transcription start site and the initiation methionine, the resultant transgenic fish became mutant alleles.
Conclusion: With its simplicity, design flexibility, and high efficiency, we propose that CRISPR/Cas9-mediated knock-in via NHEJ will become a standard method for the generation of transgenic and mutant medaka.
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http://dx.doi.org/10.1186/s40851-017-0086-3 | DOI Listing |
Successful transgenesis in model organisms has dramatically helped us understand gene function, regulation, genetic networks, and potential applications. Here, we introduce the universal single-copy knock-in system (Universal SKI System or U-SKI), designed for inserting any transgene by CRISPR/Cas9 in the genome. The Universal SKI System takes advantage of a plasmid (pSKI), which can also be used for extrachromosomal arrays, to facilitate the insertion of a transgene at specific safe harbor loci on each autosomal chromosome.
View Article and Find Full Text PDFJ Neurosci Methods
December 2024
Department of Neurology, University of Iowa; The Iowa Neuroscience Institute. Electronic address:
Background: Dopamine is a powerful neuromodulator of diverse brain functions, including movement, motivation, reward, and cognition. D1-type dopamine receptors (D1DRs) are the most prevalently expressed dopamine receptors in the brain. Neurons expressing D1DRs are heterogeneous and involve several subpopulations.
View Article and Find Full Text PDFNat Biotechnol
December 2024
Full Circles Therapeutics, Cambridge, MA, USA.
The use of adeno-associated viruses (AAVs) as donors for homology-directed repair (HDR)-mediated genome engineering is limited by safety issues, manufacturing constraints and restricted packaging limits. Non-viral targeted genetic knock-ins rely primarily on double-stranded DNA (dsDNA) and linear single-stranded DNA (lssDNA) donors. dsDNA is known to have low efficiency and high cytotoxicity, while lssDNA is challenging for scaled manufacture.
View Article and Find Full Text PDFBiochim Biophys Acta Mol Cell Res
December 2024
Friedrich-Alexander-Universität Erlangen-Nürnberg, Department of Anesthesiology, Krankenhausstraße 12, 91054 Erlangen, Germany. Electronic address:
Objective: Transgenic mice with fluorescent protein (FP) reporters take full advantage of new in vivo imaging technologies. Therefore, we generated a TRPC5- and a TRPA1-reporter mouse based on FP C-terminal fusion, providing us with better alternatives for studying the physiology, interaction and coeffectors of these two TRP channels at the cellular and tissue level.
Methods: We generated transgenic constructs of the murine TRPC5- and TRPA1-gene with a 3*GGGGS linker and C-terminal fusion to mCherry and mTagBFP, respectively.
Aging Cell
December 2024
School of Pharmacy, Nanjing University of Chinese Medicine, Nanjing, Jiangsu, China.
While previous research has demonstrated the therapeutic efficacy of telomerase reverse transcriptase (TERT) overexpression using adeno-associated virus and cytomegalovirus vectors to combat aging, the broader implications of TERT germline gene editing on the mammalian genome, proteomic composition, phenotypes, lifespan extension, and damage repair remain largely unexplored. In this study, we elucidate the functional properties of transgenic mice carrying the Tert transgene, guided by precise gene targeting into the Rosa26 locus via embryonic stem (ES) cells under the control of the elongation factor 1α (EF1α) promoter. The Tert knock-in (TertKI) mice harboring the EF1α-Tert gene displayed elevated telomerase activity, elongated telomeres, and extended lifespan, with no spontaneous genotoxicity or carcinogenicity.
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