Localization of ChM-I transcripts in the decidua. Expression of ChM-I (A, D, and G), TIMP-3 (B and E), and MMP-9 (C, F, and H) transcripts analyzed by in situ hybridization using semi-serial sections of 6.5 (A-C) and 7.5 (D-F) days p.c. mouse decidual capsules. Expression of Prl8a2 (I) and Prl3d1 (a marker for trophoblasts; J) transcripts were also examined at 7.5 days p.c. Boxed areas in panels D and F are magnified in panels G and H, respectively. Note that, at 7.5 days p.c., ChM-I transcripts were broadly detectable in the primary decidua surrounding the implanting embryo and in MMP-9-positive cells (arrowheads in panel C and F), whilst TIMP-3 transcripts (arrowheads in panel E) were marginally detected at the mesometrial side. All images are representative of at least three independent experiments. epc, ectoplacental cone; em, embryo; dec, decidua. Bars in panels A-F and I-J, 300 μm; bars in panels G-H, 100 μm.