Figure 3. DSPP and MEPE are expressed in human and mouse salivary glands. Representative staining of DSPP protein (panel A, DPP portion, LFMb-21) in human parotid and message (panel B, DSP portion) in human submandibular ducts. A similar limited distribution is seen for human MEPE protein in the parotid ducts (panel C, LFMb-33) and message (D) in submandibular ducts. As was the case for OPN, BSP, and DMP1, male mouse submandibular glands are positive for MEPE message (F) in both seromucous acini and non-GCT ducts. The DSPP protein is located only in the ducts in the female mouse submandibular gland (E), when an antibody to the DSP domain (LF-153) is used. White arrows indicate intercalated ducts. Treatment with proteinase K during in situ preparation destroys the fast-red counterstaining properties of mouse nuclei. Bar: 50 µm.