huDNM2 Mouse

The DNM2 gene encodes the dynamin-2 protein, a key GTPase that provides energy through GTP hydrolysis and plays a central role in membrane remodeling and vesicular trafficking. It drives vesicle formation and release by "constricting" and severing the neck of the cell membrane—a process crucial for maintaining cellular function. In muscle cells, dynamin-2 functions are particularly prominent: it not only participates in basic endocytic processes but also maintains the structural integrity of the T-tubule system (a critical membrane structure for transmitting nerve signals and triggering muscle contraction) and interacts with cytoskeletal proteins such as actin to preserve the structural stability of muscle fibers ^[1-2].

Mutations in the DNM2 gene cause a range of muscle disorders, the most prominent of which is centronuclear myopathy (CNM). CNM is a group of heterogeneous diseases classified by inheritance patterns into X-linked recessive (MTM1-associated), autosomal dominant (DNM2-associated), and autosomal recessive (BIN1- or RYR1-associated) forms. DNM2-CNM is the most common autosomal dominant subtype, with diverse clinical manifestations ranging from severe neonatal onset to slow progression in adulthood. Its clinical features include muscle weakness, involvement of facial and ocular muscles, and respiratory impairment. Histologically, muscle biopsies show abnormal central localization of nuclei in fibers, accompanied by uneven muscle fiber size and fibrosis ^[2-4].

Unlike most loss-of-function mutations, DNM2-CNM is mainly caused by gain-of-function mutations, with common variants at sites such as R465W, R369W, and S619L. These mutations lead to abnormally increased GTPase activity and excessive polymerization of the dynamin-2 protein, which in turn disrupts endocytic processes, T-tubule structure, and calcium homeostasis, induces autophagic disorders and abnormal myonuclear localization, and ultimately results in progressive muscle degeneration ^[4-6]. Current therapeutic strategies focus on inhibiting the overexpression of DNM2. Antisense oligonucleotide (ASO) therapy has emerged as the most promising approach; for example, the drug IONIS-DNM2-2.5Rx can specifically silence DNM2 mRNA. In preclinical models, it significantly improves muscle function, repairs T-tubule defects, and extends survival. It has currently obtained Fast Track designation and Orphan Drug designation from the U.S. FDA, demonstrating favorable translational potential ^[7-8].

huDNM2 mouse is a humanized model constructed via gene editing technology, in which the sequence of the murine Dnm2 gene (from the ATG start codon to the TAG stop codon) is replaced with the sequence of the human DNM2 gene (from the ATG start codon to the 3'UTR). Homozygous males are infertile. huDNM2 mouse can be used for mechanistic research on centronuclear myopathy (CNM) and preclinical studies of DNM2-targeted drugs.