Figure 5

Evidence that the major PR isoform in human fetal membranes at term is the 60 kDa isoform. (Panel a) Protein extracts from fetal membrane samples that had decidua attached (lane 1) and fetal membranes that had the decidua scraped away (lane 2) were compared with extracts from term amnion (lane 3), chorion (lane 4) and decidua (lane 5) that were obtained from crude tissue separation methods and from term placenta (lane 6), myometrium (lane 7) and breast cancer (T47D cell) extracts (lane 8). The antibody clones used were 1A6 (upper series) and C-20 (lower series) that detect all PR isoforms (see lane 8). (Panel b) Confirmation that the antibodies detect the 60 kDa PR-C isoform was obtained by immunoblotting an extract obtained from human choriocarcinoma (BeWo) cells transiently transfected with a human PR-C expression plasmid and probed with C-20 antibodies (-) or C-20 antibodies pre-adsorped with immunising peptide (+).