RESUMEN
Precise single-base editing in Xenopus tropicalis would greatly expand the utility of this true diploid frog for modeling human genetic diseases caused by point mutations. Here, we report the efficient conversion of C-to-T or G-to-A in X. tropicalis using the rat apolipoprotein B mRNA editing enzyme catalytic subunit 1-XTEN-clustered regularly interspaced short palindromic repeat-associated protein 9 (Cas9) nickase-uracil DNA glycosylase inhibitor-nuclear localization sequence base editor [base editor 3 (BE3)]. Coinjection of guide RNA and the Cas9 mutant complex mRNA into 1-cell stage X. tropicalis embryos caused precise C-to-T or G-to-A substitution in 14 out of 19 tested sites with efficiencies of 5-75%, which allowed for easy establishment of stable lines. Targeting the conserved T-box 5 R237 and Tyr C28 residues in X. tropicalis with the BE3 system mimicked human Holt-Oram syndrome and oculocutaneous albinism type 1A, respectively. Our data indicate that BE3 is an easy and efficient tool for precise base editing in X. tropicalis.-Shi, Z., Xin, H., Tian, D., Lian, J., Wang, J., Liu, G., Ran, R., Shi, S., Zhang, Z., Shi, Y., Deng, Y., Hou, C., Chen, Y. Modeling human point mutation diseases in Xenopus tropicalis with a modified CRISPR/Cas9 system.
Asunto(s)
Anomalías Múltiples/genética , Albinismo Oculocutáneo/genética , Sistemas CRISPR-Cas , Cardiopatías Congénitas/genética , Defectos del Tabique Interatrial/genética , Deformidades Congénitas de las Extremidades Inferiores/genética , Mutación Puntual , Deformidades Congénitas de las Extremidades Superiores/genética , Xenopus/embriología , Animales , Secuencia de Bases , Femenino , Genotipo , Humanos , MasculinoRESUMEN
Microcin C7 (McC), widely distributed in enterobacteria, is a promising antibiotic against antibiotic resistance [...].
Asunto(s)
Bacteriocinas/metabolismo , Escherichia coli/fisiología , Bacteriocinas/síntesis química , Bacteriocinas/química , Membrana Celular/metabolismo , Permeabilidad de la Membrana Celular , Activación Enzimática , Estructura Molecular , Espectrometría de Masa por Láser de Matriz Asistida de Ionización DesorciónRESUMEN
Transparent immunodeficient animal models not only enhance in vivo imaging investigations of visceral organ development but also facilitate in vivo tracking of transplanted tumor cells. However, at present, transparent and immunodeficient animal models are confined to zebrafish, presenting substantial challenges for real-time, in vivo imaging studies addressing specific biological inquiries. Here, we employed a mitf-/-/prkdc-/-/il2rg-/- triple-knockout strategy to establish a colorless and immunodeficient amphibian model of Xenopus tropicalis. By disrupting the mitf gene, we observed the loss of melanophores, xanthophores, and granular glands in Xenopus tropicalis. Through the endogenous mitf promoter to drive BRAFV600E expression, we confirmed mitf expression in melanophores, xanthophores and granular glands. Moreover, the reconstruction of the disrupted site effectively reinstated melanophores, xanthophores, and granular glands, further highlighting the crucial role of mitf as a regulator in their development. By crossing mitf-/- frogs with prkdc-/-/il2rg-/- frogs, we generated a mitf-/-/prkdc-/-/il2rg-/- Xenopus tropicalis line, providing a colorless and immunodeficient amphibian model. Utilizing this model, we successfully observed intravital metastases of allotransplanted xanthophoromas and migrations of allotransplanted melanomas. Overall, colorless and immunodeficient Xenopus tropicalis holds great promise as a valuable platform for tumorous and developmental biology research.
Asunto(s)
Anuros , Pez Cebra , Animales , Citoplasma , Xenopus/genética , Pez Cebra/genética , Factor de Transcripción Asociado a Microftalmía/genética , Factor de Transcripción Asociado a Microftalmía/metabolismoRESUMEN
In humans, germline TP53 mutations predispose carriers to a wide spectrum of cancers, which is known as Li-Fraumeni syndrome (LFS). To date, the association of melanomas with LFS remains unestablished. No melanomas have been reported in any P53-modified mouse models either. In this study, we show that targeted disruption of P53 at the DNA-binding domain in Xenopus tropicalis recapitulates LFS, with the formation of soft-tissue sarcomas and pancreatic ductal adenocarcinoma. Interestingly, 19% of the 14-month-old tp53Δ7/Δ7 homozygotes and 18% of tp53+/Δ7 heterozygotes spontaneously developed small nevi and non-invasive melanomas. Large invasive melanomas were also observed in other older homozygous mutants, with about 7.9% penetrance. Our data suggest that more dermatologic investigation of LFS patients should be able to settle the association of melanoma with LFS in epidemiology. Our model is also valuable for further investigation of the molecular mechanism underlying melanoma progression upon germline alteration of the tp53 locus.