Comparison of RNA expression of conditional Nmi knockout mammary epithelial cells to the wildtype control

The goal of this study was to compare mRNA from mammary epithelial cells of 3 mammary-specific Nmi knockout FVB with corresponding wildtype control. This was performed to obtain clues to the signaling pathways that were impacted in the mammary epithelial cells upon knocking-out Nmi expression. To determine how the loss of Nmi contributed to a hyper-proliferative phenotype during puberty and lactation, we performed global RNAseq analysis from enriched mammary epithelial organoids from lactation day1 (L1), the time when Nmi protein expression in normal mammary epithelium is at its highest level. We compared 2 groups with 3 mice/group. We used second and third mammary glands of each mouse. These glands were isolated from mice on the first day of lactation, minced and dissociated in digestion medium (HBSS containing collagenase I (Sigma Aldrich, St. Louis, MO) (1mg/mL) and Pronase (Sigma Aldrich) (0.1mg/mL)) for two hours at 37C with shaking. Epithelial organoids were washed in PBS and enriched by pulse centrifugation to 1500rpm at least three times before subsequent assays.