Figure 2

Wip1 is required for STAT5 activation in a subset of luminal cells. (A, B) Confocal immunofluorescence of mammary gland sections from virgin wild-type (WT, A) and Wip1-knockout (KO, B) mice, detecting phosphorylated signal transducer and activator of transcription 5 (P-STAT5, red) and the luminal cell marker cytokeratin-8 (CK8, green). Middle panels, enlarged sections of images shown in A and B. White arrows, representative luminal cells with the strongest P-STAT5-positive signal for that genotype. Red signal outside context of CK8 is nonspecific staining of erythrocytes. Control staining without primary antibody can be found in Additional file 4. (C, D) Same set of tissue samples probed with antibodies against STAT5 (Total-STAT5, red) and cytokeratin-8 (CK8, green). (E) Quantification of the percentage of phospho-STAT5-positive cells in WT (blue bar) and Wip1 KO mice (green bar). Values are presented as the mean proportions from five mice/group ± SD. ***P < 0.001. (F, G) Outgrowths from WT and Wip1 KO mammary epithelial cells 8 weeks after transplantation into WT cleared mammary fat pads and probed for P-STAT5 (red) and cytokeratin-8 (green). DAPI counterstain indicates cell nuclei (gray). Scale bar, 10 μm.