A new autosomal-recessive mouse mutant with progressive motor neuronopathy (pmn) is described. Homozygotes develop paralysis of the hindlimbs during the third week of life. Soon thereafter the forelimbs also become weak, and all mice die six to seven weeks after birth. Heterozygotes are normal. Skeletal muscles show neurogenic atrophy without histological signs of reinnervation. Axonal degeneration apparently starts at the endplates and is prominent in the sciatic nerve and its branches and the phrenic nerve. Axonal sprouts are abundant. There is no evidence of demyelination, and unaffected nerve fibers are normally myelinated. Sensory axons are spared. Almost all distal motor axons have disappeared in four to five weeks after birth. Ventral nerve roots show a reduced diameter of the largest fibers but no fiber deficits. The ventral horn cells show slight chromatolysis. The corticospinal tract is normal, but in terminally ill animals the fasciculus gracilis, the rubrospinal tract and possibly also reticulospinal fibers degenerate. The brain is histologically normal. The disease manifests itself in a dying-back fashion in the distal portion of the motor neurons and may represent an animal model of hereditary motor neuron diseases in man.
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Cells Dev
January 2025
Embryology Research Unit, Children's Medical Research Institute, University of Sydney, and School of Medical Sciences, Faculty of Medicine and Health, University of Sydney, NSW, Australia.
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College of Chemistry and Materials Science, Zhejiang Normal University, No. 688 Yingbin Road, Jinhua, Zhejiang Province, 321004, China. Electronic address:
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January 2025
Graduate Program in Human Genetics, University of Miami Miller School of Medicine, 1501 NW 10th Avenue (M-860), Miami, FL 33136, USA.
Primary mitochondrial disorders are most often caused by deleterious mutations in the mitochondrial DNA (mtDNA). Here, we used a mitochondrial DddA-derived cytosine base editor (DdCBE) to introduce a compensatory edit in a mouse model that carries the pathological mutation in the mitochondrial transfer RNA (tRNA) alanine (mt-tRNA) gene. Because the original m.
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February 2025
Department of Molecular Microbiology, Washington University in St. Louis, School of Medicine, St. Louis, MO 63130.
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Seaver Autism Center for Research and Treatment, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA.
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