Generation and Characterization of a <i>Rdh1‐iCre</i> Line to Study Uterine Glandular Biology

The uterus is an essential organ for fetal development in most mammals. Uterine glands, highly conserved structures in the mammalian uterus, play critical roles in the establishment and maintenance of pregnancy and have been implicated in the pathogenesis of uterine diseases, including endometrial cancer and endometriosis. Previous studies have shown that Retinol dehydrogenase 1 (Rdh1) is specifically expressed in the glandular epithelium (GE) from the onset of gland formation through adulthood. In this study, to develop a GE-specific Cre driver line, we generated Rdh1-iCre mice by introducing an improved Cre recombinase (iCre) into the Rdh1 locus using the CRISPR/Cas9 system. To evaluate the utility of this model, Rdh1-iCre mice were crossed with ROSA26-H2B-mCherry reporter mice, and Cre-dependent reporter expression was analyzed. Robust mCherry fluorescence was observed throughout the uterine glands at 2 weeks after birth, coinciding with the active elongation and branching of the GE. These results demonstrate that the Rdh1-iCre mouse line is a valuable and highly efficient tool for investigating the physiological roles of uterine glands during development and pregnancy, as well as their contribution to the progression of GE-derived uterine diseases.