Fig 1: Stn/siglec-g underlies the embryo implantationin vivo. Experimental design. (B) Representative immunofluorescent images for sTn in uterine endometrium at GD4. (C) Implanted embryos (arrows) on GD6 were visualized by blue dye. The number of implanted embryos on the two uterine sides treated as indicated (Uterine horn injection of IgG or anti-sTn antibodies on GD3) was statistically analyzed. (D) Reprehensive immunofluorescent images for Siglec-G in blastocyst flushed from the uterine lumen on GD4. (E) Implanted embryos (arrows) on GD6 were visualized by blue dye. The number of impanated embryos on the two uterine sides treated as indicated (Uterine horn injection of IgG or anti-Siglec-G antibodies on GD3) was statically analyzed. (F) Immunoblots of CD44 in input and immunoprecipitated samples derived from pooled whole cell lysates (WCL) of uteri tissues at GD4 (n = 3) with anti-sTn antibodies or IgG. (G-i) Schematic for protein interaction assay. (G-ii) Immunoblot of CD44 in samples from rmSiglec-G (lane 1), rmSiglec-G co-incubated with pooled WCL from uteri tissues at GD4 (n = 3) (lane 2), rmSiglec-G co-incubated with pooled WCL from uteri tissues at GD4 (n = 3) in the presence of IgG (lane 3) or anti-sTn antibodies (lane 4). Ponceau S staining of the NC membrane was shown to prove the equal protein loading. Bars represent 10 μm (B) and 20 μm (D). LE, luminal epithelium; TE, trophectoderm. The uterine horn injection assay was performed independently four times. IP and Protein interaction assays were performed for three independent experiments, and representative immunoblot images were shown. **P<0.01; *** P<0.001.