Figure 7.

ACTC1 expression in human placenta samples over gestation. (A–D) ACTC1 strongly associates with primitive syncytium and emerging STB on the secondary villus. (E–H) Six weeks 6 days human placenta was immunostained for STB markers CGA (E, G) and CTB/EVT marker KRT7 (F, H) at lower (E, F) and higher (G, H) magnifications. (I–O) are placental villi from the first trimester at gestational ages (I) 5 weeks 5 days, (J) 6 weeks 6 days, (K) 7 weeks 6 days, (L) 8 weeks 2 days, (M) 13 weeks, (N) 20 weeks 6 days and (O) term. Signals detected within the mesenchymal villous core in O, and intervillous space in K are erythrocyte autofluoresence. (P) CTCF quantification of positive CTB/STB regions. First trimester samples showed higher fluorescence intensity values than second trimester and term. Best fit line is y = x + x². R² = 0.61. (M–P) Scale bars = 100 µm.