Amyotrophic lateral sclerosis (ALS), also known as motor neuron disease, is a fatal progressive neurodegenerative disease. The disease is caused by the degeneration and death of motor neurons that control skeletal muscles in the central nervous system, leading to gradual muscle weakness and atrophy, and ultimately complete loss of voluntary movement control by the brain ^[1]. Unlike Alzheimer’s disease, ALS does not necessarily affect higher brain functions. On the contrary, late-stage patients can maintain clear thinking and retain memories, personality, and intelligence before the onset of the disease. The known ALS-causing genes include SOD1, ALS2, TARDBP, and FUS, among others. FUS is a multifunctional DNA/RNA binding protein typically located in the cell nucleus and can shuttle between the nucleus and cytoplasm. FUS protein plays an important role in RNA transcription, splicing, and microRNA processing. Mutations in the FUS gene are closely related to frontotemporal lobar degeneration/dementia (FTLD-FUS) and amyotrophic lateral sclerosis (ALS-FUS). More than 50 FUS gene mutations have been identified in familial and sporadic ALS patients, most of which are autosomal dominant and most of which affect the nuclear localization signal (NLS) of FUS protein ^[2]. ALS-FUS patients have a histopathological feature of FUS protein mislocalization to the cytoplasm and formation of FUS-positive inclusions in spinal motor neurons and glial cells. However, in current cases, only some patients exhibit FUS mislocalization, and changes in the nuclear function of FUS mutants can also cause ALS. Studies have found that FUS pathological mice can induce neurodegeneration without cytoplasmic pathology or obvious mislocalization, which strongly suggests that the nuclear toxic function of FUS mutants may be a potential pathogenic mechanism ^[2]. Most FUS-targeting drugs in development are gene therapies, including antisense oligonucleotides (ASOs). The ASO drug ION363 developed by Ionis Pharmaceuticals can effectively reduce abnormal expression of FUS in diseased mice ^[3]. Humanizing mouse genes, given the genetic differences between animals and humans, can accelerate the development of FUS-targeted gene therapy for clinical use. This strain is a mouse Fus gene humanized model and can be used for research on ALS. The homozygous huFUS mice are viable and fertile. In addition, based on the independently developed TurboKnockout fusion BAC recombination technology, Cyagen can also generate hot mutation models based on this strain (e.g., FUS (p.R521C)) and provide customized services for specific mutations to meet the experimental needs in pharmacology and other fields related to ALS.

Amyotrophic lateral sclerosis (ALS), also known as motor neuron disease, is a fatal progressive neurodegenerative disease. The disease is caused by the degeneration and death of motor neurons that control skeletal muscles in the central nervous system, leading to gradual muscle weakness and atrophy, and ultimately complete loss of voluntary movement control by the brain ^[1]. Unlike Alzheimer’s disease, ALS does not necessarily affect higher brain functions. On the contrary, late-stage patients can maintain clear thinking and retain memories, personality, and intelligence before the onset of the disease. The known ALS-causing genes include SOD1, ALS2, TARDBP, and FUS, among others. FUS is a multifunctional DNA/RNA-binding protein that is usually localized within the nucleus but can also shuttle between the nucleus and the cytoplasm. The FUS protein plays an important role in processes such as RNA transcription, splicing, and microRNA processing. Mutations in the FUS gene are closely associated with frontotemporal lobar degeneration/dementia (FTLD-FUS) and amyotrophic lateral sclerosis (ALS-FUS). Typically, the histopathological feature of ALS-FUS patients is the mislocalization of the FUS protein to the cytoplasm in spinal cord neurons and glial cells, and the formation of FUS-positive inclusions. However, based on current cases, only a portion of patients exhibit FUS mislocalization, and changes in the nuclear function of FUS mutants can also trigger ALS. Pathological FUS mice can induce neurodegeneration in the absence of cytoplasmic pathological changes or even significant mislocalization, which strongly indicates that the toxic nuclear function of FUS mutants may be a potential pathogenic mechanism. More than 50 FUS gene mutations have been found in patients with familial ALS and sporadic ALS, and the vast majority of them are inherited in an autosomal dominant pattern ^[2]. The mutant FUS protein generated by the R521C mutation in the FUS gene can form a stable complex with the wild-type (WT) FUS protein, interfere with normal protein interactions, cause DNA damage, and exhibit abnormal dendritic and synaptic phenotypes in the mouse brain and spinal cord. There is evidence that FUS-R521C mice have defects in transcription and splicing of genes responsible for regulating dendritic growth and synaptic function ^[3]. The FUS-targeted drugs under research are mainly gene therapy drugs, such as antisense oligonucleotides (ASOs). The ASO drug (ION363) developed by Ionis has entered phase 3 clinical trials. This drug can effectively reduce the abnormal expression of FUS in diseased mice ^[4]. Most gene therapy methods act on human genes. Considering the genetic differences between animals and humans, humanizing the mouse genes will help accelerate the advancement of FUS-targeted gene therapies into the clinical stage. This model is a humanized model. Gene editing technology is used to replace the endogenous mouse Fus gene with a human FUS gene fragment carrying the R521C mutation. B6-hFUS*R521C mice can be used for the research of amyotrophic lateral sclerosis (ALS) and frontotemporal lobar degeneration/dementia (FTLD). In addition, based on the technological innovation of TurboKnockout fusion BAC recombination independently developed by Cyagen, customized services can be provided for different point mutations to meet the experimental needs of researchers.

G6pd2 is located on chromosome 5 of mice. SgRNA and ssDNA were designed using Nuclease Technology; G6pd2 conditional knockout mice were obtained by high-throughput electroporation of fertilized eggs. After sexual maturity, sperm were collected for cryopreservation.

Hsd17b3 is located on chromosome 13 of mice. Nuclease Technology will be used to design sgRNA; Hsd17b3 knockout mice will be obtained by applying high-throughput electroporation of fertilized eggs. After sexual maturity, sperm were collected for cryopreservation.