Fig. 7. Multiple conditions regulate expression of HLA-G isoforms in trophoblast cells.
The vCTB cell (center) may proliferate and drive toward the maternal decidua (lower portion of figure). Acquisition of higher levels of isoform-specific HLA-G mRNAs occurs as a consequence of low oxygen levels in the decidua. Forces driving protein expression in these cells are not known. Alternatively, vCTB cells may differentiate into sTB (upper portion of figure). Epidermal growth factor appears to increase HLA-G5 and reduce HLA-G6 mRNA in these cells and to promote exclusive expression of HLA-G5 in the differentiated syncytium.