A Cxcl15 Cre Recombinase Mouse Model Useful to Study Gland Development in the Uterus.

The mammalian uterus contains glands in the endometrium that develop only or primarily after birth. In the mouse, endometrial glands govern post implantation pregnancy establishment via regulation of blastocyst implantation, stromal cell decidualization, and placental development. Here, we describe a new uterine glandular epithelium (GE) specific Cre recombinase mouse line that is useful to study endometrial gland development and function. Utilizing CRISPR-Cas9 genome editing, improved Cre recombinase (iCre) was inserted into the endogenous C-X-C motif chemokine ligand 15 (Cxcl15) gene. Cxcl15 mRNA, Cxcl15 protein, and Cxcl15-iCre recombinase activity were specific to the developing GE of the uterus. Cxcl15-iCre mice were crossed with floxed Foxa2 mice to conditionally delete Foxa2 specifically in the glands of the neonatal mouse uterus. This conditional deletion of Foxa2 in the developing neonatal uterus resulted in adult mice that lacked Foxa2 in the GE of the uterus, and the adult mice were infertile. The studies described here establish that Cxcl15-iCre mice are a valuable resource to elucidate and explore mechanisms regulating the development and function of glands in the uterus.