Cerebellar nuclei excitatory neurons regulate developmental scaling of presynaptic Purkinje cell number and organ growth.

For neural systems to function effectively, the numbers of each cell type must be proportioned properly during development. We found that conditional knockout of the mouse homeobox genes and in the excitatory cerebellar nuclei neurons (eCN) leads to reduced postnatal growth of the cerebellar cortex. A subset of medial and intermediate eCN are lost in the mutants, with an associated cell non-autonomous loss of their presynaptic partner Purkinje cells by birth leading to proportional scaling down of neuron production in the postnatal cerebellar cortex.

Lhx1 is required in Müllerian duct epithelium for uterine development.

The female reproductive tract organs of mammals, including the oviducts, uterus, cervix and upper vagina, are derived from the Müllerian ducts, a pair of epithelial tubes that form within the mesonephroi. The Müllerian ducts form in a rostral to caudal manner, guided by and dependent on the Wolffian ducts that have already formed. Experimental embryological studies indicate that caudal elongation of the Müllerian duct towards the urogenital sinus occurs in part by proliferation at the ductal tip.

STAT3 regulates uterine epithelial remodeling and epithelial-stromal crosstalk during implantation.

Embryo implantation is regulated by a variety of endometrial factors, including cytokines, growth factors, and transcription factors. Earlier studies identified the leukemia inhibitory factor (LIF), a cytokine produced by uterine glands, as an essential regulator of implantation. LIF, acting via its cell surface receptor, activates the signal transducer and activator of transcription 3 (STAT3) in the uterine epithelial cells.

Diethylstilbestrol induces vaginal adenosis by disrupting SMAD/RUNX1-mediated cell fate decision in the Müllerian duct epithelium.

Women exposed to diethylstilbestrol (DES) in utero frequently develop vaginal adenosis, from which clear cell adenocarcinoma can arise. Despite decades of extensive investigation, the molecular pathogenesis of DES-associated vaginal adenosis remains elusive. Here we report that DES induces vaginal adenosis by inhibiting the BMP4/Activin A-regulated vaginal cell fate decision through a downregulation of RUNX1.

Critical tumor suppressor function mediated by epithelial Mig-6 in endometrial cancer.

Endometrial cancer is preceded by endometrial hyperplasia, unopposed estrogen exposure, and genetic alterations, but the precise causes of endometrial cancer remain uncertain. Mig-6, mainly known as a negative regulator of the EGF receptor, is an important mediator of progesterone signaling in the uterus, where it mediates tumor suppression by modulating endometrial stromal-epithelial communications. In this study, we investigated the function of Mig-6 in the uterine epithelium using a tissue-specific gene knockout strategy, in which floxed Mig-6 (Mig-6(f/f)) mice were crossed to Wnt7a-Cre mice (Wnt7a(cre+)Mig-6(f/f)).

Functional analysis of ectodermal β-catenin during external genitalia formation.

β-catenin is a molecule belonging to the armadillo family of proteins that is a crucial core-component of cellular adherens junctions, and a component of the canonical Wnt-signaling pathway. We attempted to analyze the functional significance of ectodermal-derived β-catenin during the development of the mouse genital tubercle, a mammalian anlage of the external genitalia. For this purpose, the conditional loss of function mouse mutant Wnt7a-Cre;β-cat(f/f) was utilized.

Stromal-to-epithelial transition during postpartum endometrial regeneration.

Endometrium is the inner lining of the uterus which is composed of epithelial and stromal tissue compartments enclosed by the two smooth muscle layers of the myometrium. In women, much of the endometrium is shed and regenerated each month during the menstrual cycle. Endometrial regeneration also occurs after parturition.

The engrailed homeobox genes are required in multiple cell lineages to coordinate sequential formation of fissures and growth of the cerebellum.

The layered cortex of the cerebellum is folded along the anterior-posterior axis into lobules separated by fissures, allowing the large number of cells needed for advanced cerebellar functions to be packed into a small volume. During development, the cerebellum begins as a smooth ovoid structure with two progenitor zones, the ventricular zone and upper rhombic lip, which give rise to distinct cell types in the mature cerebellum. Initially, the cerebellar primordium is divided into five cardinal lobes, which are subsequently further subdivided by fissures.

Spatially restricted and developmentally dynamic expression of engrailed genes in multiple cerebellar cell types.

The cerebellum is a highly organized structure partitioned into lobules along the anterior-posterior (A-P) axis and into striped molecular domains along the medial-lateral (M-L) axis. The Engrailed (En) homeobox genes are required for patterning the morphological and molecular domains along both axes, as well as for the establishment of the normal afferent topography required to generate a fully functional cerebellum. As a means to understand how the En genes regulate multiple levels of cerebellum construction, we characterized En1 and En2 expression around birth and at postnatal day (P) 21 during the period when the cerebellum undergoes a remarkable transformation from a smooth ovoid structure to a highly foliated structure.

Uterine epithelial estrogen receptor α is dispensable for proliferation but essential for complete biological and biochemical responses.

Female fertility requires estrogen to specifically stimulate estrogen receptor α (ERα)-dependent growth of the uterine epithelium in adult mice, while immature females show proliferation in both stroma and epithelium. To address the relative roles of ERα in mediating estrogen action in uterine epithelium versus stroma, a uterine epithelial-specific ERα knockout (UtEpiαERKO) mouse line was generated by crossing Esr mice with Wnt7a-Cre mice. Expression of Wnt7a directed Cre activity generated selective deletion of ERα in uterine epithelium, and female UtEpiαERKO are infertile.

A mesenchymal perspective of Müllerian duct differentiation and regression in Amhr2-lacZ mice.

The Müllerian ducts give rise to the female reproductive tract, including the Fallopian tubes, uterus, cervix, and anterior vagina. In male embryos, the Müllerian ducts regress, preventing the formation of female organs. We introduced the bacterial lacZ gene, encoding beta-galactosidase (beta-gal), into the AMHR-II locus (Amhr2) by gene targeting in mouse embryonic stem (ES) cells to mark Müllerian duct differentiation and regression.

Cellular mechanisms of Müllerian duct formation in the mouse.

Regardless of their sex chromosome karyotype, amniotes develop two pairs of genital ducts, the Wolffian and Müllerian ducts. As the Müllerian duct forms, its growing tip is intimately associated with the Wolffian duct as it elongates to the urogenital sinus. Previous studies have shown that the presence of the Wolffian duct is required for the development and maintenance of the Müllerian duct.