Myosin VIIA (MYO7A) (MYO7A)

Myosin VIIA (MYO7A) is an unconventional motor protein that is essential for the structural integrity and intracellular trafficking within the sensory hair cells of the inner ear and the retinal pigment epithelium (RPE) and photoreceptors of the eye [1, 2]. It functions by moving along actin filaments to transport various cargoes, including melanosomes and phagosomes, and is critical for the renewal of photoreceptor outer segments [1]. Mutations in the MYO7A gene are the primary cause of Usher syndrome type 1B, a genetic disorder characterized by congenital deafness, vestibular dysfunction, and progressive vision loss due to retinitis pigmentosa [2]. Because the MYO7A coding sequence is approximately 6.7 kb, it exceeds the carrying capacity of standard adeno-associated virus (AAV) vectors, which has led to the development of specialized gene augmentation strategies such as lentiviral vectors (e.g., UshStat) or dual-AAV systems [3, 4]. These therapies aim to deliver a functional copy of the gene to retinal cells to restore protein expression and halt the progression of blindness [4]. (Sources: [1] UniProt P51807; [2] NIH MedlinePlus; [3] ClinicalTrials.gov NCT01505062; [4] Nature Communications DOI:10.1038/ncomms5527)

Other names

Myosin-7AUSH1BDFNB2DFNA11NSRD2Unconventional myosin-VIIa

Gene augmentation therapy involves delivering a functional copy of the MYO7A cDNA to target retinal cells (specifically the retinal pigment epithelium and photoreceptors) to restore the production of functional Myosin VIIA protein, thereby compensating for loss-of-function mutations [3, 4].