Even in genomes lacking operons, a gene's position in the genome influences its potential for expression. The mechanisms by which adjacent genes are co-expressed are still not completely understood. Using lactation and the mammary gland as a model system, we explore the hypothesis that chromatin state contributes to the co-regulation of gene neighborhoods. The mammary gland represents a unique ...

The lactating mammary gland is composed of multiple cell types that tightly coordinate the accumulation, production, and secretion of milk components, including essential metals such as zinc (Zn). Our previous studies in animal and cell models implicated the Zn transporter Zip3 (Slc39a3) in mammary gland Zn acquisition. Herein, we investigated this hypothesis directly by utilizing Zip3-null mic...

Disruptions in polarity and mitotic spindle orientation contribute to the progression and evolution of tumorigenesis. However, little is known about the molecular mechanisms regulating these processes in vivo. Here, we demonstrate that Polo-like kinase 2 (Plk2) regulates mitotic spindle orientation in the mammary gland and that this might account for its suggested role as a tumor suppressor. Pl...

Disruptions in polarity and mitotic spindle orientation contribute to the progression and evolution of tumorigenesis. However, little is known about the molecular mechanisms regulating these processes in vivo. Here, we demonstrate that Polo-like kinase 2 (Plk2) regulates mitotic spindle orientation in the mammary gland and that this might account for its suggested role as a tumor suppressor. Pl...

The transplantation of primary mammary epithelial cells after adenovirus-Cre-mediated recombination provides a new approach for the study of specific gene function during mammary gland development and in breast cancer. Most mammary-gland-specific promoters identified to date are regulated by lactogenic hormones. They are expressed predominantly in lobuloalveolar cells during pregnancy and lacta...

Mammary gland development is a complex process that is dependent on interactions between the developing mammary epithelium and the surrounding stromal tissues. We show that mice lacking the triglyceride synthesis enzyme acyl CoA:diacylglycerol transferase 1 (DGAT1) have impaired mammary gland development, characterized by decreased epithelial proliferation and alveolar development, and reduced ...

Sialomucin complex (SMC, Rat Muc4) is a heterodimeric glycoprotein complex consisting of a mucin subunit ASGP-1 (ascites sialoglycoprotein-1) and a transmembrane subunit ASGP-2, which can act as a ligand for the receptor tyrosine kinase ErbB2. SMC is highly expressed on the surface of ascites 13762 rat mammary adenocarcinoma cells, approximately 100 times the level in lactating mammary gland an...

The existence of numerous neuropeptides in milk, in concentrations that exceed those in maternal plasma, is well established. It is still unclear whether these neuropeptides are produced by the mammary gland or that the gland concentrates them from the general circulation. In this study, we have examined the possibility that the genes of these neuropeptides are expressed in the rat mammary glan...

MicroRNA (miRNA) plays a key role in development and specific biological processes, such as cell proliferation, differentiation, and apoptosis. Extensive studies of mammary miRNAs have been performed in different species and tissues. However, little is known about porcine mammary gland miRNAs. In this study, we report the identification and characterization of miRNAs in the lactating mammary gl...

We have generated a new and improved transgenic mouse strain that permits a temporally controlled expression of transgenes throughout mammary gland development. High expression of the tetracycline-regulatible transactivator (tTA) under control of the mouse mammary tumor virus long terminal repeat (MMTV-LTR) is restricted to mammary epithelial cells and the salivary gland. The novel MMTV-tTA mou...