Fig. 1.

Northern blotting of genes exhibiting elevated expression in HC11 cells undergoing lactogenic differentiation. a. HC11 mouse mammary epithelial cells were cultured in complete medium with EGF for 4 days post confluence followed by incubation in the media without EGF for 24 h. The cells were then stimulated with differentiation media containing dexamethasone (10⁻⁶ M), insulin(5 µg/ml) and prolactin (5 µg/ml) for 0, 12, 24, 48, and 72 h. RNA was extracted and used for northern blots. The probes are described in Materials and Methods. The fold changes of gene expression of each probe normalized to β-actin is shown. b. Northern blotting of genes exhibiting elevated expression in HC11 cells hybridized to RNA from mouse mammary glands. The probes used in part A were hybridized to northern blots of RNA extracted form mouse mammary glands at various stages of pregnancy and lactation. The RNAs are from pregnancy days 10, 12 and 16; lactation days 1 and 3; involution days 1 and 7; and NP represents RNA from non-pregnant mammary glands of adult female mice. The blots were hybridized to β-actin as a loading control. C. HC11 cells undergoing lactogenic differentiation. Control = untreated cells, DIP = cells exposed to DIP for 5 days. Top panel: cells at magnification 200X; bottom panel: cells at magnification of 500X