The Lecithin Retinol Acyltransferase (LRAT) gene encodes a retinol-esterifying enzyme located in the endoplasmic reticulum, serving as a key enzyme in vitamin A metabolism within the visual system by catalyzing the esterification of all-trans-retinol to all-trans-retinyl ester. In addition to its critical role in the visual cycle, LRAT is essential for retinol metabolism in tissues such as the liver, testes, and small intestine. Mice lacking the Lrat gene exhibit a sharp decrease in intracellular retinyl esters and impaired vision. Mutations in this gene are associated with early-onset severe retinal dystrophy and Leber congenital amaurosis 14 ^[1]. LRAT-positive cells are primarily located in the narrow space between hepatocytes and sinusoidal endothelial cells, known as the perisinusoidal space (Space of Disse). Additionally, LRAT is expressed in the extraembryonic components, intestines, liver, midbrain, and reproductive system. At the cellular level, LRAT is mainly distributed in the rough endoplasmic reticulum and multivesicular bodies of hepatic stellate cells (HSC).

The Lrat-P2A-tdTomato-T2A-CreERT2 mouse is created by integrating the P2A-tdTomato-T2A-CreERT2 expression cassette into the stop codon of the mouse Lrat gene using gene editing technology. Under the control of the mouse Lrat gene regulatory elements, tamoxifen-inducible CreERT2 recombinase is expressed. The expression pattern of CreERT2 recombinase is similar to that of the endogenous Lrat gene. Using 2A peptides (P2A and T2A) prevents decreased protein activity and downstream gene expression during multi-gene expression. Additionally, this model carries a red fluorescent protein (tdTomato) expression element, which can be used for cell lineage tracing. When Lrat-P2A-tdTomato-T2A-CreERT2 mice are crossed with mice containing loxP sites, Cre recombinase-mediated loxP site recombination is expected to occur in the progeny’s hepatic stellate cells and other cells expressing the Lrat gene.