The expression pattern of Cat C mRNA and protein in the control brain. ISH (A and B) and IHC (C and D) staining were performed in control mice. The rectangles in A and C which included the CA2 area were enlarged into B and D, respectively. Cat C gene was predominantly expressed in the CA2 neurons of the hippocampus (B and D), interneurons (dotted arrow in C), choroid plexus (thick solid arrows in A and C), leptomeninges (open arrow in C) and vascular cells (thin solid arrow in C). Scale bar = 100 μm (A, C); 20 μM (B, D). n = 5 per condition. Cat C, cathepsin C; IHC, immunohistochemistry; ISH, in situ hybridization.