Analysis of Cell Type-specific Expression of CK1 epsilon in Various Tissues of Young Adult BALB/c Mice and in Mammary Tumors of SV40 T-Ag-transgenic Mice

Casein kinase 1 epsilon (CK1 epsilon) is involved in various cellular processes, including cell growth, differentiation, and apoptosis, vesicle transport, and control of the circadian rhythm. Deregulation of CK1 epsilon has been linked to neurodegenerative diseases and cancer. To better understand the cell type-specific functions of CK1 epsilon, we determined its localization by immunhistochemistry in tissues of healthy, young adult BALB/c mice and in mammary tumors of SV40 T-antigen-transgenic mice. CK1 epsilon expression was found to be highly regulated in normal tissues of endodermal, mesodermal, and ectodermal origin and in neoplastic tissue of mammary cancer. The data presented here give an overview of CK1 epsilon reactivity in different organs under normal conditions and outline changes in its expression in mammary carcinomas. Our data suggest a cell/organ type-specific function of WE and indicate that tumorigenic conversion of mammary glands in SV40 T-antigen-transgenic mice leads to downregulation of CK1 epsilon. This manuscript contains online supplemental material at http://www.jhc.org. Please visit this article online to view these materials. (J Histochem Cytochem 58:1-15, 2010)