B6-huGUCY2D Mouse

Gucy2e, which is the gene encoding mouse retinal guanylate cyclase 1 (RetGC1), is a key enzyme in the retina responsible for synthesizing the second messenger cyclic guanosine monophosphate (cGMP). cGMP plays an important role in the process of retinal phototransduction. Especially when restoring the dark state, it regulates the opening and closing of cGMP-gated calcium-sodium channels (CNG) and controls the influx of calcium ions (Ca2+). Mutations in Gucy2e can lead to the loss of function of retinal guanylate cyclase 1, thereby affecting the normal function of retinal photoreceptor cells ^[1]. Studies have shown that mutations in the Gucy2e gene are one of the main causes of Leber congenital amaurosis type 1 (LCA1). In humans, the GUCY2D gene encodes RetGC1, and its mutations lead to the occurrence of LCA1 ^[2]. Gene therapy offers a new treatment strategy for LCA1 patients. By delivering the GUCY2D gene or its normal copy into retinal photoreceptor cells via adeno-associated virus (AAV) vectors, it is possible to restore the function of rod and cone cells and improve visual behavior. In addition to gene therapy, researchers have explored other therapeutic approaches. For example, using double-stranded RNA interference (RNAi) technology can reduce the expression of the GUCY2D gene, thereby slowing the progression of retinal degeneration ^[1-2]. Apart from LCA1, the GUCY2D gene is also associated with other retinal diseases; recessive mutations in the GUCY2D gene cause cone-rod dystrophy (CORD). In a mouse model of retinitis pigmentosa (RP), knocking down the expression of the Gucy2e gene can increase the survival rate of photoreceptors and slow down the process of retinal degeneration ^[3].

The B6-huGUCY2D mouse is a humanized model constructed through gene-editing technology, in which the sequences from p.A55 to 3'UTR of the endogenous mouse Gucy2e gene are replaced with the sequences from p.A52 to 3'UTR of the human GUCY2D gene. The murine signal peptide is remained. This model can be used for research on diseases such as Leber congenital amaurosis type 1 (LCA1), cone-rod dystrophy (CORD), and retinitis pigmentosa (RP), as well as for screening, development, and preclinical evaluation of GUCY2D-targeted therapeutics.