Figure 2.

The progression of HLA-G molecule expression in the human preimplantation stage. Summarized from Yao YQ et al. (2005) (22). HLA-G3 and –G4 represent the predominant spliced transcripts in the whole preimplantation stage, followed by HLA-G1, -G2, and -G5. HLA-G6 did not appear until the blastocyst stage. After implantation, HLA-G1 and –G5 were expressed toward differentiation into trophectoderm and gradually faded away in the inner cell mass during development. Interestingly, shed HLA-G1 and HLA-G5 were detected in follicle and female blood but not in male gametogenic cell-like sperm.