Acute expression of cyclin D1 in mouse mammary gland using the tetracycline system

Analysis of mammary glands from tet-inducible (rtTA) transgenic mice expressing cyclin D1 (Ccnd1). MMTV-rtTA transgenic mice (MMTV-Mouse Mammary Tumor Virus promoter) were cross-mated to cyclin D1 transgenic mice under the control of the tet operon. 8-week-old tetracycline-inducible cyclin D1/rtTA bi-transgenic pregnant female mice (12 days postcoitus) were treated with doxycycline through drinking water supplementation at a final concentration of 2 mg/ml. Control mice were rtTA transgenics alone and were treated in the same manner. After 7 days of doxycycline treatment, the mice were sacrificed and mammary glands taken for RNA isolation. Results provide insight into the in vivo gene expression pattern regulated by cyclin D1 through acute induction. Two separate control mice positive for the MMTV-rtTA transgene were compared to 3 separate cyclin D1/rtTA bi-transgenic female mice.