Figure 4

Claudin 7 in mouse mammary tumors. (a) Black bars, mRNA levels by real-time reverse transcriptase polymerase chain reaction in the four murine mammary tumors and the lactating gland, chosen for comparison because it, like the tumors, contains a large proportion of epithelial cells. All values are normalized to ribosomal RNA. Gray bars, Ratio of claudin 7 mRNA to keratin 19 mRNA. Error bars represent two SEM. (b) Claudin 7 distribution in paraffin section of the transplantable tumor TM4. The stain is localized to the perimembrane cytoplasm in all cells and excluded from nuclei. The arrowheads mark the point in which tight-junction stain would be expected if tight junctions were to form; however, no ZO1 stain was detected in the section. Scale bar, 20 μm.