Biology subjects

Arudkumar, J.

Publications and source records attributed to Arudkumar, J..

3 recordsLinked to original sources

bioRxiv2024

Generation and characterisation of mouse models of Duchenne Muscular Dystrophy (DMD)

CRISPR-Cas9 gene-editing technology has revolutionised the creation of precise and permanent modifications to DNA, enabling the generation of diverse animal models for investigating potential treatments. Here, we provide a protocol for the use of CRISPR-Cas9 to create murine models of Duchenne Muscular Dystrophy (DMD) along with a step-by-step guide for their phenotypic and molecular characterisation. The experimental procedures include CRISPR microinjection of embryos, molecular testing at the DNA, RNA, and protein levels, forelimb grip strength testing, immunostaining and serum creatine kinase (CK) testing. We further provide suggestions for analysis and interpretation of the generated data, as well as the limitations of our approach. These protocols are designed for researchers who intend to generate and use mouse models to study DMD as well as those seeking a detailed framework of phenotyping to contribute to the broader landscape of genetic disorder investigations.

molecular biology↗

bioRxiv2024

Megabase-scale Transgene De-Duplication to Generate a Functional Single-Copy Full-Length Human DMD Transgenic Mouse Model

The development of sequence-specific precision treatments like CRISPR gene-editing therapies for Duchenne Muscular Dystrophy (DMD) requires sequence humanised animal models to enable the direct clinical translation of tested strategies. The current available integrated transgenic mouse model containing the full-length human DMD gene, Tg(DMD)72Thoen/J (hDMDTg), has been found to have two copies of the transgene per locus in a tail-to-tail orientation, which does not accurately simulate the true copy number of the DMD gene. This duplication also complicates the analysis when testing CRISPR therapy editing outcomes, as large genetic alterations and rearrangements can occur between the cut sites on the two transgenes. To address this, we performed long read nanopore sequencing on hDMDTg mice to better understand the structure of the duplicated transgenes. Following that, we performed a megabase-scale deletion of one of the transgenes by CRISPR zygotic microinjection to generate a single-copy, full-length, humanised DMD transgenic mouse model (hDMDTgSc). Functional, molecular, and histological characterisation show that the single remaining human transgene retains its function and rescues the dystrophic phenotype caused by endogenous murine Dmd knockout. Our unique hDMDTgSc mouse model can potentially be used to further generation of DMD disease models, suited for the pre-clinical assessment of sequence-specific therapies.

molecular biology↗

bioRxiv2021

Optimized nickase- and nuclease-based prime editing in human and mouse cells

Precise genomic modification using prime editing (PE) holds enormous potential for research and clinical applications. Currently, the delivery of PE components to mammalian cell lines requires multiple plasmid vectors. To overcome this limitation, we generated all-in-one prime editing (PEA1) constructs that carry all the components required for PE, along with a selection marker. We tested these constructs (with selection) in HEK293T, K562, HeLa and mouse embryonic stem (ES) cells. We discovered that PE efficiency in HEK293T cells was much higher than previously observed, reaching up to 95% (mean 67%). The efficiency in K562 and HeLa cells, however, remained low. To improve PE efficiency in K562 and HeLa, we generated a nuclease prime editor and tested this system in these cell lines as well as mouse ES cells. PE-nuclease greatly increased prime editing initiation, however, installation of the intended edits was often accompanied by extra insertions derived from the repair template. Finally, we show that zygotic injection of the nuclease prime editor can generate correct modifications in mouse fetuses with up to 100% efficiency. In summary, PE-nuclease and the PEA1 plasmids provide new tools to generate intended edits with high efficiency.

molecular biology↗