FIG. 3.

Expression of c-Rel in transgenic female MMTV-c-rel breast tumors. Mammary glands were removed from virgin WT FVB/N (WT Virgin) or transgenic line 16 (16 Virgin) mice and from tumor (T) and grossly normal (N) tissues of multiparous line 14 and 16 transgenic mice. The identification number given to the individual mice is indicated in parentheses. Characteristics of the tumor samples are given in the Table 1. (A) Transgenic c-rel expression. RNA was prepared from mammary gland and tumor tissues, and samples subjected to RT-PCR with primers specific for transgenic c-rel, as in the legend to Fig. 1. (B) Total protein c-Rel expression. Nuclear extracts were prepared, and samples (40 μg) subjected to immunoblot analysis of c-Rel levels. Coomassie blue staining of SDS-PAGE gels was used as control for equal loading (bottom panel). While the overall levels of staining were essentially equivalent, the analysis revealed that the patterns of protein expression are different between tumors, WT and normal transgenic mammary gland samples. This variability likely results from differences in cell type composition in these tissues.